OPPOSITION Leader Tony Abbott has vowed to keep population growth in Australia to below 30 million by 2050 and will more than halve the current immigration rate to achieve it.

And future population targets would be tied to a target range, much like the inflation rate settings determined by the Reserve Bank, set by Cabinet on the advice of an independent commission.

Releasing the Coalition's draft population policy, the federal Opposition Leader yesterday issued a direct challenge to Prime Minister Kevin Rudd's "big Australia" policy, claiming it has set a target of 36 million by 2050.

Mr Abbott said he would also, for the first time, make it Liberal Party policy to restrict migrant intake to Australia to a two-thirds ratio of skilled workers to non-skilled workers.

Blog with Tony at midday Friday: Rudd's wrong population target

The Coalition believes it is on an election winner when it comes to immigration and population issues and Mr Abbott yesterday chose the hot point of anti-immigration sentiment in western Sydney to make the point.

"The current immigration numbers are utterly unsustainable," Mr Abbott said. "What we are saying with certainty is that we cannot continue to take 300,000 people a year."

Mr Abbott said that, if elected, the Coalition would also relax the red tape for skilled migrant visas - the 457 visa system - and also would apply a critical skills test to industries to determine if and where real occupational needs existed.

Mr Abbott told The Daily Telegraph his policy discussion paper was a formal rejection of Mr Rudd's "target" of 36 million people by 2050.

That is the predicted size of the Australian population at an annual net migration rate of 180,000.

However, at the current 300,000 figure, Australia's population would be closer to 43 million people.

To achieve a population target of fewer than 36 million people, the current migration rates would have to be virtually halved.

And the Coalition policy would give an expanded role to the Productivity Commission, which would be tasked with setting a population target range that would cover the short, medium and long term.

Population Minister Tony Burke responded to Mr Abbott's policy, claiming the Government did not have a target of 36 million.

"It's a lie," he said. "It's merely a projection from Treasury. It was not a target. Not an ambition. Not a policy."

Originally published as Abbott cracks down on population