Labour leader David Cunliffe took the attack to Prime Minister John Key as the Government backed a convention centre deal with SkyCity, claiming there was nothing "Trader John" would not trade.
Mr Cunliffe said the New Zealand International Convention Centre Bill - which passed its final vote yesterday by 61 votes to 59 - bailed out big business and went against the interests of New Zealand families.
"The Prime Minister's personal style is on display for the world to see. Business calls him a map with no compass. He's known colloquially as Trader John and there is nothing, Sir, nothing that he will not trade."
The Labour leader claimed the Government had given SkyCity special treatment, and cited the Auditor-General's investigation into the "flawed" tender process for a convention centre.
Finance Minister Bill English said the Government had carefully managed the risk of increased gambling facilities at SkyCity, and these risks were outweighed by the economic benefits of the deal.
Mr English said 1000 people would be employed during the construction of the convention centre and 800 staff would be employed once it was built. He estimated it would generate $90 million a year in spending by delegates and an increase to GDP of $49 million.
SkyCity will build a $400 million international convention centre capable of hosting 3500 delegates as part of a deal which will extend their licence for 30 years and allow the casino to expand its gambling floor.
SkyCity chief Nigel Morrison said these concessions would begin when the company signed a construction contract - expected to be in the second half of next year.
Mr Cunliffe said Labour would not "dynamite" a half-built convention centre at SkyCity if it came into power. But his party would not agree to a clause in the bill which required the Government to compensate SkyCity if it changed laws before 2048.
Before the debate, the Green Party called on all MPs to declare any shareholdings in SkyCity.
Co-leader Metiria Turei said disclosure rules applied if an MP, their spouse, children or a trust they had an interest in had shares in SkyCity.