South Australian opposition leader Steven Marshall says the state budget is built on unrealistic forecasts which will fail to deliver a return to surplus.

The South Australian government’s plans to return its budget to surplus in 2015 are built on “voodoo economics”, the state opposition says.

Delivering his budget reply speech in parliament on Tuesday, opposition leader Steven Marshall said key forecasts in the budget defied belief.

The state’s economy is forecast to grow by 2.2 per cent in 2014/15 and by 2.5 per cent the following year, underpinned by a lift in housing construction and stronger mining export returns.

That is expected to bring the budget back to a $406 million surplus in 2015/16 after a $479 million deficit this financial year.

But Mr Marshall said the forecasts were unrealistic when thousands of jobs had been lost in the past year and business confidence was dwindling.

“It’s voodoo economics,” he told parliament.

“Let’s just hold hands, sing Kumbaya, and hope magically our economy here in South Australia will improve.”

The SA government should learn from Liberal governments in Queensland and Victoria where jobs growth was on the rebound, Mr Marshall said.

Treasurer Tom Koutsantonis took to Twitter to hit back at Mr Marshall, saying he was “still waiting” for the opposition leader to lay out an alternative plan to create jobs.