No consistent wording for the warning appears in the Oaths Act 1867, Family Law Rules 2004 or the JP Handbook.
Suggested warnings:
Witness: Do you understand that you may be sent to prison, fined or both, if you make a false statement?
Deponent responds: Yes, or I do.
Witness: Do you understand that if the declaration is found to be untruthful, there are severe penalties which include imprisonment.
Declarant responds: Yes, or I do.
Witness: Do you solemnly, sincerely and truly affirm and declare, that the contents of this, your affidavit, are true and correct, to the best of your knowledge and belief?
Deponent responds: Yes, or I do.
Witness: Do you swear by almighty God that the contents of this, your affidavit, are true and correct, to the best of your knowledge and belief?
Deponent responds: Yes, or I do.
Affidavits and associated references are discussed in detail in the Affidavits page.