MPs from the Labour Party's South Auckland strongholds are divided over a bill which would legalise same-sex marriage, with two concerned it could seriously hurt the party's support in its heartland electorates.
Labour MP for Mangere Su'a William Sio said he would oppose fellow MP Louisa Wall's bill when it came up for a conscience vote, and called for it to be withdrawn.
Mangere was one of three crucial Labour electorates in South Auckland, and he felt the wide opposition from constituents to the bill, particularly from Pacific Islanders, could cost the party at the next election.
Labour MP for Manukau East Ross Robertson was undecided on his vote, but said changing marriage laws had stirred "disquiet" in his electorate, which he described as the "spiritual belt" of New Zealand.
Asked whether Labour's association with the bill could hurt its vote at the next election, he said: "It has the potential to do that."