National list MP Tau Henare is challenging Labour's beleaguered Te Atatu MP, Chris Carter, to resign and force a by-election.
Stripped of his shadow foreign affairs portfolio because of the way he used his ministerial credit card when he was a cabinet minister, and in party leader Phil Goff's bad books for refusing to front the media, Mr Carter has been sent on leave and told to think about his future.
Mr Henare, who stood against Mr Carter in Te Atatu at the last election, says the MP should quit.
Mr Goff says it is up to Mr Carter whether or not he has a future with the party. He sent the MP on leave on Tuesday, saying he has been under great stress and needs time to sort his life out.
He said on Wednesday he had yet to talk to Mr Carter about his future and he could not say how long the MP would be absent from Parliament.
Carter apologises 'unreservedly'
After initially appearing unwilling to do so, Mr Carter issued an apology on Tuesday for his expenses while travelling overseas as a minister and said he intends to work hard for his electorate and the Labour Party.
The statement says it is clear a public apology is demanded and required, and he apologises unreservedly to the public. It says that, when under pressure, his temperament can make him appear as if he is not contrite or embarrassed when in fact he is.
Mr Goff says the statement was the minimum he demanded of the MP, who would now have to demonstrate he has the ability and judgment to regain the party's trust.
Unhappy about refusal to answer questions
After Labour's caucus at Parliament on Tuesday morning, Mr Carter made a brief statement to the media. He said he was grateful for his new shadow conservation portfolio, but would not answer any questions and walked away angrily.
Mr Goff subsequently said that he was very unhappy about that, because he expected Mr Carter to acknowledge why the public is concerned about excessive travel by ministers and MPs.
He said Mr Carter's position as conservation spokesperson, and his No 13 caucus ranking, are now in doubt. Expulsion from the caucus is not an option at present, he said, but he is not ruling out further demotion down the ranks.
Former Labour Party president Mike Williams says Mr Carter has tested the patience of his caucus and the public and needs to go home, cool down and then come back to Parliament showing appropriate contrition.
Mr Williams says Mr Goff's treatment of Mr Carter shows his strength as the party leader.