It is the third time Garrett has been before the courts.
He has a previous conviction for assault in Tonga in 2002 and was discharged without conviction three years later for stealing the identity of a dead child to obtain a passport.
Garrett is due back in court on his drink-driving charge in February next year.
Last month Garrett appeared before a the Lawyers and Conveyancer's Committee where he was censured, suspended from holding a lawyer's practising certificate for a year and ordered to pay court costs of $8430 to the Law Society.
The hearing related to a false affidavit he had sworn to the court while he faced the charge of stealing the identity of a dead child to get a passport in 2005.
Garrett, who was a practising lawyer at the time, did not mention the Tongan conviction.
He told the court: "The worst I could be accused of is incurring some parking and speeding fines.''
Garrett, who quit Parliament in September last year, had championed the controversial three strikes policy.
