A witness must take an oath or make an affirmation before giving sworn evidence: Evidence Act 1995, s 21; see “witness” in Dictionary section of the Evidence Act. A witness may still give unsworn evidence in accordance with s 13. Section 21 is in adamantine terms, and failure to comply with it is a procedural irregularity going to the root of proceedings: RJ v R [2010] NSWCCA 263 at [48]–[49].

Similarly a person acting as an interpreter must take an oath or make an affirmation before acting as an interpreter: s 22.

A witness or an interpreter may choose whether to take an oath or to make an affirmation and the court is to advise the individual of the right to choose: s 23.

It is not necessary an oath be taken on a religious text: s 24(1). An oath is effective regardless of whether the person had any religious belief or understood the nature and consequences of the oath: s 24(2).

See also Oaths and affirmations in the Criminal Trial Courts Bench Book at [1-600]ff, which includes [1-605] Procedure for administering an oath upon the Koran.

Sections 21(4), 22(2) and Sch 1 provide for the forms of oaths and affirmations.