Mr Hodgman will deliver his alternative budget today.

He said the Liberals had allocated $3.5 million to provide up to 500 grants of $7000 in 2012-13 to build new first homes.

``This would be on top of the $7000 grant from the federal government, meaning first home builders would receive $14,000 in support,'' he said.

Mr Hodgman said his party's alternative budget would protect frontline services and put downward pressure on the cost of living.

The opposition would also cut the budget for the ministerial vehicle fleet by 20 per cent.

Opposition Treasury spokesman Peter Gutwein said the opposition would stick to its policy of creating a smaller, more efficient public service, which would deliver savings equivalent to 1700 jobs.

One of the sources of revenue identified in last week's state budget was revenue from the federal government's price on carbon, which will not be included in the opposition's budget.

Mr Gutwein said federal leader Tony Abbott would be prime minister within the next couple of years and would roll back the price on carbon.

He also said the opposition would have no option but to go into debt as it could only respond to the financial circumstances outlined by the government in its budget.

The opposition will use the government's GST forecasts despite labelling them wildly optimistic.

Deputy Premier Bryan Green criticised the opposition for what he described as hypocrisy in relation to the carbon price - ``They're handing back money at the same time as they're suggesting it shouldn't be in place.''