Freezing politicians' pay and making MPs take economy-class flights would do more to restore integrity than a building industry watchdog, says independent senator John Madigan.

Senator Madigan has launched a scathing critique of the government as it makes a last-ditch effort to get crossbench approval for the Australian Building and Construction Commission.

The government has failed to get a majority in the senate to pass the ABCC laws and a second failure would provide a double-dissolution election trigger.

With Labor and the Greens firmly opposed to the laws, the government must win over six out of eight crossbenchers.

But the Victorian senator said restoring integrity – a key argument being put in support of the ABCC – needed to go beyond setting up one body overseeing one industry.

“We have a major integrity deficit right across society,” Senator Madigan said.

Apart from bringing in a national integrity commission, a government with integrity would lead by example in freezing politicians’ pay and making them fly economy class, he said.

“That’s what the majority of Australians would expect us to do,” he said.

“But they are not interested in the parliament being the tapestry of the nation – it’s a bloody club, run by a cabal of people who sit up in first class and say: `Do as we say, not as we do’.”

Two key backers of the ABCC bill, Family First’s Bob Day and the Liberal Democrats’ David Leyonhjelm, have withdrawn their support for the bill over the government’s senate voting reform plans.

“I think the government is resigned to the fact it won’t get through,” Senator Leyonhjelm said.