Union wants super profits tax to pay for social housing

National secretary Zach Smith will outline the ambitious plan during a speech to the National Press Club, putting pressure on the governing Labor Party.

Mr Smith said more than 750,000 dwellings were desperately needed in Australia, and it would cost more than $500 billion to close the gap, which would be comfortably covered by a super profits tax.

"The money exists, the wealth exists, but it doesn't exist in ordinary Australian households," he will say in Canberra on Tuesday.

"It exists in the profit columns of a very small and very elite group of corporations."

Mr Smith said the government could and must step in to fix the housing problem.

"The state has a role to play, and Australians want the state to play it," he said.

The union boss said the tax would only apply to 0.3 per cent of companies that were making the biggest profits.

Research conducted by Oxford Economics Australia, which was commissioned by the construction workers' union, said an economy-wide super profits tax would be able to fund the forecast $28 billion per year required to close the housing gap.

The research firm found a gap of 190,000 social dwellings and 559,000 affordable ones, an overall increase of 114,000 since 2014.

Mr Smith said the proposed tax would be a circuit breaker.

"We must first square up to an obvious truth: to fix a housing affordability crisis you must build more affordable houses," he will say.

"We do need to move more boldly than we've done for a while. 

"We need big structural reform aimed at a serious long-term fix."

The policy follows the Labor government's proposed $10 billion Housing Australia Future Fund, which has stalled in the Senate.

That fund would aim to build 30,000 social and affordable homes in the next five years.

The Oxford Economics research said the government's proposed 30,000 homes would be well shy of the number of homes needed to fix the problem.

Government Services Minister Bill Shorten said the future fund would be critical to ensuring more housing is built, while rejecting the plan for a super profits tax.

"Housing is a problem. There is no doubt that we need to develop more supply. There's no doubt that people are doing it tough in the rental market," he told ABC TV on Tuesday.

"The government has no plans that I'm aware of to have any sort of super tax, so I think the government's got a strategy and I think we should stay the course and back in what we know."

After Mr Smith launches the super profits tax campaign at the National Press Club, the CFMEU will take it to Labor's national conference next month, calling for it to be included in the party's policy platform.

"This reform could end homelessness in Australia, it could boost productivity, it could lift millions out of poverty and distress," Mr Smith will say.

"I know we're not used to thinking this big anymore, but there's such a strong appetite out there for an idea like this one."