Labour is attacking United leader MP Peter Dunne for giving the Government a wafer-thin majority on its asset sales bill.
It was passed 61-60 on Tuesday with National backed by the ACT Party and Mr Dunne, UF's only MP.
"This obnoxious law was passed thanks to a politician who got just 0.6 percent support from Kiwis at the last election," Labour leader David Shearer said.
"It's a travesty, Peter Dunne and National MPs will pay dearly for their actions."
Mr Shearer says that he does not, however, support a tweet sent by Labour MP Megan Woods, comparing the Government to Adolf Hitler.
"Hitler had a pretty clear manifesto that he campaigned and won on ... does this make what he did OK?," Ms Woods tweeted yesterday.
Labour's state-owned enterprises spokesman Clayton Cosgrove told Parliament Mr Dunne was "a dead man crawling" and would lose his seat in 2014.
The bill allows the Government to sell 49 percent of the shares in four state-owned energy companies and Mr Dunne says he backed it because "it is in the best long term interests of this country".
Mr Dunne says the Government's alternative was to borrow the $6 billion it expects to raise from the share floats.
"The bill gives New Zealanders - who have been whacked in recent years by shonky financial institutions that toppled like crooked dominoes - a strong, safe investment option for the future," he said.
Mr Dunne signed a support agreement with the Government after last year's election and is minister of revenue.