John Tamihere will have to wait until November to find out if the Labour Party will take him back as a member - and it could depend on whether others in the party raise objections.
Mr Tamihere confirmed he had applied online to become a member again and had sent a note to the party informing it of this.
Party secretary Tim Barnett said Mr Tamihere would be subject to more scrutiny than usual because of his high public profile.
It was "unusual but not unheard of" for membership to be refused.
The party's leading council would have to decide if there were any formal objections to Mr Tamihere rejoining. None had yet been received.
"From my point of view, I would just look at the record of membership in the past and anything on things he might have allegedly said or done that might have brought the party into disrepute."
Asked whether Mr Tamihere's criticism of Labour on the talkback radio show he hosted could count against him, Mr Barnett said it could be looked at if someone raised a specific concern.
"But I don't think it would get down to a lengthy examination of everything he's said and done in the last few years."
Other than the prohibition on membership of another political party, there were no specific criteria in the constitution to reject a membership application.
The council would seek input from Mr Tamihere's local electorate - Waitakere - and a final decision would be made at the party's New Zealand Council meeting at the end of November.
To stand for the party in an election, a candidate has to have been a party member for at least one year.
Mr Tamihere is yet to confirm whether he will seek selection as a candidate - but he has made it clear that if he does stand again he would try to get the Waitakere electorate.
He said he knew the constitution well and it would be "unusual" if his application was vetted by the New Zealand council.
He said he knew the processes of Labour very well and did not believe there were grounds to refuse his application. He had already been censured and apologised for his past indiscretion in criticising colleagues, and was now older andwiser.
"You've just got to go with the process and if the process is flawed, you have a go at it."
Mr Tamihere's time as an MP ended when he lost the Tamaki Makaurau seat to Maori Party co-leader Pita Sharples.By Claire Trevett @CTrevettNZH Email Claire