National leader Bill English signed a banknote at a campaign event in Nelson on Tuesday, calling in to question whether the law on defacing bank notes applies to him.
"I have been signing some bank notes because I've been asked by enthusiastic supporters who like to collect bank notes with signatures on them," Mr English told Newshub.
Section 28 of the currency Act states "a person must not deliberately deface, disfigure or mutilate any banknote without the permission of the Bank."
When asked if Mr English had permission to sign the notes, he responded: "Now that you've raised the issue I'll go and consult my lawyer."
The law on defacing banknotes, listed on the Reserve Bank of New Zealand website states that "No person shall without the prior consent of the Bank, wilfully deface, disfigure, or mutilate any bank note."
Further, the law states "the person who is party to the defacement, disfigurement or mutilation of any bank note" should not pay away, part with, put into circulation, demand payment of, or deposit into any bank that bank note.
Those who break this law are liable on conviction to a fine of up to $1,000.
A Reserve Bank spokesperson told Newshub the Bank have an understanding with certain people, saying that for Sir Edmund Hillary, Governors General, Prime Ministers and Finance Ministers signing notes is "acceptable behaviour".
The bank does not encourage the signing of bank notes but they do have an understanding for "suitable purposes".