UPDATED 4:00pm: Labour's accusing the Prime Minister of not trusting his MPs after the Government told all National politicians to vote for the SkyCity convention centre deal, despite it being a personal vote.
The Speaker says MPs will be able to vote with their consciences when the first reading of the Bill comes up tomorrow.
Opposition leader David Shearer says gambling is traditionally a conscience issue, and Labour MPs will be able to vote as they see fit.
He says it is disappointing John Key won't let his MPs do the same and says that's because the Bill would fail if he did.
But the Prime Minister says his MPs aren't being given a conscience vote on the deal because they campaigned for it at the last election.
Other MPs will be able to exercise their consciences rather than toeing their party line.
John Key says voting for it is a no brainer.
"This is going to deliver a thousand jobs in construction, 900 ongoing jobs, hundreds of thousands of visitors to Auckland, an economic uplift for the economy."
Greens join attack on National
National is under further attack for forcing its MPs to vote for the legislation, with Greens co-leader Metiria Turei today saying this of the Economic Development Minister Steven Joyce.
"The Minister is frightened of supporting a genuine conscience vote because he knows that this Bill, this deal, is hanging by a one vote thread."
Steven Joyce defended the decision saying the Government's pretty confident about votes on his side of the house.
"There are members on the other side of the House who might like the opportunity to vote for jobs and growth through this Bill.
"I note that the Labour leader, for example, has allowed a conscience vote in this matter, and given the state of the Labour Caucus I expect a few more votes from them."
National MPs to back legislation
National MPs look set to back the legislation, even with the ability to exercise a personal vote on the legislation.
List MP Claudette Hauiti says she will be backing the Bill.
"Because that's where my conscience lies and that's where the party is going to be voting."
And Minister of Commerce Craig Foss will be backing it.
"My conscience will be thinking about the thousand-plus jobs the whole conference centre will create."
Minister of Police Anne Tolley will also support it.
"The National Party have campaigned on this, this is part of what we are about."
Speaker rules for a conscience vote
Speaker David Carter has decided the will be a conscience vote because gambling related issues traditionally are.
But Mr Carter says at this stage it's only for the first reading because he wants to see the way the votes are cast.
"To see in fact whether all parties are taking a party position.
"If they were to take a party position, then it would seem to indicate that it's not actually being treated as a conscience vote."
Greens co-leader Metiria Turei asked for it to be a conscience vote but is resigned to the fact National, and other parties, may whip their MPs.
"But at least MPs know that they have the opportunity to vote according to their conscience.
"And many MPs will be very concerned about the social harms.
"This idea that we can have 400 extra problem gamblers is a serious issue."
Ms Turei hopes MPs take a conscience vote seriously, and that it will be enough to sink the Bill.
"This legislation is hanging by a thread, it is based on one vote.
"One vote will make the difference between this country crating 400 more problem gamblers, thousands more New Zealanders and their children suffering harm."
A government spokesman says all National MPs will vote for the bill.
A spokesman for Economic Development Minister Steven Joyce says because it is government legislation, all MPs will vote yes.