All three of the Maori Party's votes are critical if the bill is to pass, although Finance Minister Bill English has said he will veto it at the final reading anyway.
The Maori Party has taken responsibility for the stuff-up, which happened after the Party's Whip Te Ururoa Flavell was called back to his home because it was believed his daughter had gone into labour with his first grandchild.
It turned out to be a false alarm and Mr Flavell will return to Parliament today. He will seek leave to change the vote today and is understood to have obtained permission from all parties in Parliament. That will mean Ms Moroney's bill can proceed to its next stage.
Mr Flavell had contacted the Speaker and was given compassionate leave so his vote could still count, but there was a communication breakdown with National. Its junior whip Tim Macindoe instead cast the Maori Party votes as opposed to the bill.
