First-term NZ First MP Clayton Mitchell has revealed a fight with a gang member 18 years ago landed him with an assault charge and a suspended sentence.

Clayton, 43, was in charge of Tauranga's Straight Shooters Bar in 1997 when a gang member was refused entry.

NZ First MP Clayton Mitchell. Photo: File

After a physical confrontation, Clayton says the man threatened to return with a gun and finish him off.

He followed the gang member and "gave him a few lumps, I guess, is the only way to describe it."

Clayton ended up with a black eye and swollen face from the altercation.

He had instructed staff at the bar to call the police for help and was charged with assault, and received a suspended sentence.

"It was a big surprise to me that I got charged afterwards - I obviously went a bridge too far with defending myself, but I definitely at the time felt very, very afraid and having incidents where things can easily get out of hand, I thought this guy was going to go and get a gun.

The gang member, an ex-New Zealand power-lifter, had skipped bail from Rotorua and was locked up after the incident.

He was "a very big, intimidating guy," says Clayton.

A much smaller man himself, Clayton says he had to do everything he could to stay on top of the situation.

"You just don't know when you get into situations how bad they can get and how quickly they can go bad - I guess from my situation, being in hospitality for so long I've been to many picnics where they've been serving up knuckle sandwiches, I've had my jaw broken a couple of times and my nose broken, I've had knives pulled on me, I've had death threats, I've had all sorts of things, and that's just the nature of some of the places I've worked.

"You've just got to be very, very careful and make sure you keep yourself safe, make sure you come home to your family and loved ones each night or each morning."

Clayton has been upfront with NZ First about the incident and the charges laid.

"Everyone's got a past and while it's not a discussion I have with everybody every day it's also not something I'm ashamed of - these situations happen."

Clayton has a background in self defence - he is a black belt in Judo and a boxing coach, and runs classes for women to learn how to protect themselves.