Evidence Act 1995 (NSW), s 38
A party calling a witness can be permitted to cross-examine the witness in accordance with s 38 Evidence Act. Such cross-examination can only be permitted with leave and, therefore, s 192 of the Act applies. The evidence can be rejected under s 137 of the Act if it is unduly prejudicial within the terms of that section.
A prior inconsistent statement can be admissible as to the truth of its contents under s 60 of the Act.
As to unfavourable witnesses see generally: R v Le (2002) 54 NSWLR 474, Adam v The Queen (2001) 207 CLR 96, R v Ryan (No 7)  NSWSC 1160, DPP v Garrett (a Pseudonym) (2016) 257 A Crim R 509; Criminal Practice and Procedure NSW at [3-s 38.1]ff; Uniform Evidence Law at [1.2.3260]ff; and New Law of Evidence at 38.1ff.
It may be necessary to warn the jury under s 165 of the Act as to the potential unreliability of a prior inconsistent statement because of its hearsay nature.
[4-255] Suggested direction — prior inconsistent statement by a Crown witness
[If the judge wishes to explain the usual circumstances under which cross-examination occurs the following may be said:
In the usual case the party who calls a witness is not permitted to cross-examine the witness: that is, the party cannot seek to test the honesty or accuracy of the witness about the evidence given by [him/her]. In the usual case it is the opposing party who has the right to test a witness by cross-examination.]
However, in relation to the witness, [name of witness], I permitted the Crown to ask [him/her] questions concerning the evidence given by [him/her] in light of a statement that [he/she] had previously made. This was because it appeared to me that there was some inconsistency between the evidence given initially by [name of witness] when called by the Crown and what [he/she] said in the statement.
As with all witnesses, it is a matter for you to decide what if any of [name of witness] evidence you accept as honest and reliable.
You can conclude that, in spite of the previous statement made by [name of witness], the evidence given by [him/her] in Court should be accepted, either wholly or in part, and be used by you in reaching your verdict.
On the other hand you may, having regard to all the circumstances in which [name of witness] statement was made, choose to accept it either wholly or in part instead of the evidence given by [him/her] in Court. You can also choose to accept some part of what [name of witness] said in Court and what [he/she] said in the statement as long as you make your decision logically, rationally and by applying your common sense. You can also reject everything [name of witness] has said about this matter.
As I said earlier it is a matter for you to decide what, if any, of [name of witness] evidence that you accept as honest and reliable.
[If necessary add
In relation to the statement made by the witness you will take into account that it was of course not on oath. Further I warn you that it may be unreliable because [state reasons by reference to s 165 Evidence Act].]