The Labour Party's Pacific Island Affairs spokesperson, Su'a William Sio, wants fellow Labour MP Louisa Wall to withdraw her member's bill proposing the legalisation of same-sex marriage.
Mr Sio says the bill is causing deep divisions in Labour's heartland Pacific vote and could cost the party the next election and he will vote against it because of widespread resistance to it from his constituents - especially churchgoers.
He says it is the wrong bill at the wrong time.
"This issue cuts deep into fundamental beliefs and will divide the community," Mr Sio says. "There are weightier and more pressing issues, like holding John Key to account for the weakening economy and the lack of jobs - and that's where our priority ought to be."
The MP says Labour lost as many as 30,000 Pacific voters over homosexual law reform and civil unions, and the same-sex marriage bill could do the same.
Mr Sio is the MP for Mangere, the electorate with the biggest Pacific population, and his view on this issue is backed by Labour's Pacific Islands vice-president, Efu Koka, who also says the bill is likely to significantly hurt the Pacific vote at the next elections.
Opposition 'based on mistruths'
Ms Wall says a lot of opposition by Pacific churches is based on the misbelief that they will be compelled to conduct same-sex marriages.
"What I don't like," she says, "is ministers telling their congregation members that they're going to have to accept same-sex marriages in those churches.
"That's not true; and I don't want mistruths interfering in what should be a really rational debate about what a diverse New Zealand looks like and how we should all have tolerance and accept each other for who we are."
Ms Wall says her bill will allow same-sex couples to go to the state for a marriage licence and will not stop churches defining marriage as being between a man and a woman.
She says she expects the bill to be sent to a select committee at its first reading, and Pacific communities should make submissions at that stage.