Garrett appeared before four members of the New Zealanders Lawyers and Conveyancer's Committee, including four members and Judge Dale Clarkson at the Auckland District Court this morning (Friday).
He had earlier pleaded guilty to being reckless or negligent when he swore a false affidavit and omitted to tell the truth.
In her finding Judge Clarkson said the tribunal would censure Garrett and suspend him from holding a lawyer's practising certificate for a year.
She also ordered him to pay court costs of $8430 for the Law Society.
"A lawyer must not dance on the head of a pin but give up all information and be willing to disclose all information in their best interests," Judge Clarkson said.
The suspension has in effect already been served but Garrett must re-apply for a lawyer's practicing certificate.
The Law Society originally alleged he had sworn a statement and omitted to tell the truth but that charge was withdrawn.
Police had investigated Garrett but decided against laying charges in July.
Graham McCready, the Wellington man who laid a civil complaint against Trevor Mallard for punching Tau Henare, laid the complaint against Garrett with the Law Society.
Mr McCready said he thought Garrett had acted in a way that was unbecoming of a lawyer and should be struck off.
While in Parliament, Garrett pushed for the controversial 'three strikes' law and order policy.