The following will only be relevant where disputed admissions have been admitted into evidence notwithstanding s 281 Criminal Procedure Act 1986. See Bryant v R (2011) 205 A Crim R 531 at ff for examples of where that has occurred.
Prior to the Evidence Act 1995, the decision of the High Court in McKinney v The Queen (1991) 171 CLR 468 required a trial judge to warn the jury that, because of the apparent vulnerability of an accused person in police custody, they should give careful consideration to the dangers involved in convicting an accused person in circumstances where the only (or substantially the only) basis for finding that guilt has been established beyond reasonable doubt is an oral admission allegedly made while in police custody, the making of which is not reliably confirmed: McKinney v The Queen at 476.
In the course of that warning, the jury had to be told:
that it is comparatively more difficult for an accused person held in police custody without access to legal advice or other means of confirmation to have evidence available to support a challenge to police evidence alleging that an oral admission had been made, than it is for such police evidence to be fabricated,
that police officers are trained to give evidence in court, and
that it is not an easy task to decide whether a practised witness is telling the truth.
Those requirements were directed to ensuring that the accused person obtained the fair trial to which he or she is entitled: McKinney v The Queen at 476; Dietrich v The Queen (1992) 177 CLR 292 at 327–328, 333. This decision has to be read in light of the provisions of the Evidence Act set out at [2-120].
Section 165 Evidence Act requires a warning to be given to the jury that the evidence of witnesses within the various categories of suspect witnesses may be unreliable, with information as to the matters which may cause it to be unreliable, and a warning of the need for caution in determining whether to accept the evidence and the weight to be given to it: s 165(2). This must be done whenever any party so requests, unless the judge is satisfied that there are good reasons for not doing so (s 165(2) and (3)), and it is not restricted to the cases to which McKinney v The Queen was directed — where, generally, the oral admissions form the only (or substantially the only) evidence of guilt and where they were made in police custody: McKinney v The Queen at 476; R v Small (1994) 33 NSWLR 575 at 602–604. The warning, if sought by counsel, should be given where the Crown is relying upon evidence coming within the category described in the section.
The category of evidence identified by s 165(1)(f) Evidence Act is:
[O]ral evidence of questioning by an investigating official of a defendant that is questioning recorded in writing that has not been signed, or otherwise acknowledged in writing, by the defendant.
“Investigating official” is defined in the Dictionary to the Act.
Those directions must be given with the weight of the judge’s own authority: R v Richards (unrep, 03/04/98, NSWCCA) at 3 and 15. But it should be made clear that it is an issue for the jury to determine whether and to what degree weight should be given to evidence falling within s 165: R v Wilson (2005) 62 NSWLR 346;  NSWCCA 20 at .
A judge is entitled to direct the jury that evidence of pre-trial exculpatory statements of an accused could be given less weight than inculpatory admissions in the absence of testimony from the accused at trial but it is for the jury to determine the weight to be given to parts of the evidence: Mule v The Queen (2005) 79 ALJR 1573 at ff.
Where the evidence of an admission can be used by the jury as the only evidence upon which to convict an accused, the reliability of the admission must be proved beyond reasonable doubt. If it is not relied upon as the only evidence of guilt, then the warning must be given, if asked for, but the admission does not have to be proved to the criminal standard.
Evidence has been given, that the accused made certain admissions to the police. The accused has denied that [he/she] made those admissions and has suggested that this evidence is deliberately false.
[Outline the evidence and the nature of the dispute in sufficient detail to suit the circumstances of the case.]
It is not unknown for a guilty person to make full admissions to the police and then to have second thoughts and dishonestly deny having made them. However, and unfortunately, it is also not unknown for police officers to manufacture evidence against a person whom they believe has committed an offence.
There are two issues for you to decide. Were the admissions made and, if you decide that they were made, were they true?
You may think that a person would not usually admit to committing a crime unless the admissions were true, but there may be situations where a person may make a false admission. The main issue in this case, as I understand it, is whether the admissions were made at all. But the Crown must also prove that they are truthful admissions and, if there is any evidence to suggest that they are not, the Crown must refute that suggestion. [Indicate what evidence, if any might call the truth of the admissions into question, such as, for example, mental illness, personality defect or intoxication.]
In relation to the first issue, that is, whether the admissions were made, you must approach the evidence of the police with caution. This is because the circumstances in which it is alleged that the admissions were made may make the evidence unreliable. I am not telling you that you should regard this evidence as unreliable. The reliability of the evidence is a matter for you to decide. I cannot make that decision for you and nor am I trying to suggest what decision you should make. It is, however, my duty to warn you of the possibility that evidence of this kind may be unreliable and to explain why that is so. It is up to you to decide whether you accept this evidence and what weight, or significance, it should have.
There are a number of reasons why the evidence may be unreliable. Generally, they indicate that it is easier for police officers to fabricate their evidence than it is for the accused to have evidence available to challenge what they have said.
First, although police do have available to them equipment and facilities to record interviews with suspects, in this case there was no electronic recording made. Even if you accept the explanation that was given for no electronic recording being made, the fact remains that there is no confirmation that those admissions were made independent of the police who say that they were made by the accused.
Second, there was no-one present at that interview except the accused and the police. That state of affairs is not improper. The police officers were perfectly entitled to interview the accused alone. What this means, however, is that there was no independent person present who might have been able to support the accused’s challenge to the police evidence.
Another matter you should take into account is that the accused had no opportunity to make any note of [his/her] conversation with the police officers at the time of that conversation. A note made by the accused at the time might have enabled [him/her] to challenge the evidence of the police officers more persuasively.
You should also take into account that police officers are generally experienced in giving evidence in court. It is not an easy task to decide whether a practiced witness is telling the truth or not. If a witness appears to be confident and self-assured, it does not necessarily follow that the witness is giving honest evidence.]
[Refer to any other matters that may not be apparent to the jury and which may bear upon the reliability of the evidence.]
All of these matters mean that the evidence of the police as to the disputed admissions may be unreliable. For this reason, it is necessary that you approach their evidence with caution in deciding whether to accept it and what weight, or significance, you should give to it.
I repeat that I am not giving you this warning because of any opinion I have about the evidence. As I have already said, the reliability of the evidence is a matter for you to decide. This warning is one which is given in every case where this type of evidence is relied upon by the Crown.
[Indicate the arguments relied upon on this issue by both parties.]
Those are the arguments put before you. As I have said, there are two matters for you to decide. Were the admissions made? If so, were they truthful?
If you decide that the admissions were made, and that they were truthful, then you may take them into account in deciding whether the Crown has proved the guilt of the accused beyond reasonable doubt. If the admissions are the sole evidence of the accused’s guilt [if appropriate add and in this case they are], then because of the requirement that the accused’s guilt be proved beyond reasonable doubt, it follows that you must be satisfied beyond reasonable doubt that the admissions were made and that they were true.