South Australia's Treasurer Rob Lucas has foreshadowed "significant" cuts to key Government departments in next month's state budget, prompting Labor to warn of an imminent "slash and burn".

Key points: SA Treasurer Rob Lucas is promising "significant" cuts to "all departments"

SA Treasurer Rob Lucas is promising "significant" cuts to "all departments" Mr Lucas says job losses would not impact "frontline services"

Mr Lucas says job losses would not impact "frontline services" Labor says the Government is getting ready to "slash and burn"

Mr Lucas will deliver his first state budget in 17 years on September 4, after the Liberals were elected in March after four consecutive Labor terms.

On Friday, he was asked in a press conference if he would cut the Environment Department by 25 per cent.

While he did not confirm that figure, he singled out that department, as well as Treasury and the Department of Premier and Cabinet, as potentially in the firing line.

He added that all Government departments would be forced to find "efficiency dividends", and blamed Labor for leaving the state's finances in a "mess".

"The issue will be if we have to achieve savings of $250 million from the former Labor government which they left to us, and going up to $715 million in the fourth year which they left to us," he said.

"Clearly there will be significant reductions in all departments, not just the Environment Department."

But Mr Lucas said the Government will not be breaking any of its election promises, and any job cuts would not hit "frontline services".

"So agencies like Treasury, and Premier's, the Environment — all of those agencies that don't have doctors, teachers, nurses, police, child protection workers — will be agencies that will have to take their fair share of the load," he said.

The Treasurer's comments are the latest in a number of statements from the Government pointing to what Premier Steven Marshall has described as a "tough" budget.

But in what could be another significant budget announcement, Mr Marshall is expected to detail a plan to drive down the state's energy prices later this morning.

The ABC understands the plan involves energy interconnection and will be unveiled at the Liberal Party Annual General Meeting.

Labor warns of 'slash and burn'

The Government has brought in administrators KordaMentha to deal with a $250 million blackhole in health, and Mr Lucas has also been critical of the $8.5 million price tag on the Murray-Darling Basin Royal Commission.

Labor's Susan Close and Peter Malinauskas have criticised the cuts. ( ABC News: Nick Harmsen )

But Opposition Leader Peter Malinauskas said there was no reason for cuts.

"They inherited a budget with a surplus, we know that they've got record revenues as a result of additional GST money coming into the system," he said.

"There is no real justification for a slash-and-burn budget."

Labor spokeswoman Susan Close said she was concerned about potential cuts to the Environment Department.

"At a time when national parks are looking after 25 per cent of the state, when climate change means that we need to be even more vigorous in our maintenance of land quality, I am deeply concerned," she said.

"This Government doesn't care about the environment enough to fund it properly."

Mr Lucas said the Government still plans to put in a right-hand turn on the controversial North Terrace tram line, despite predictions it will cost tens of millions of dollars.

He said it was an election promise, and money would be found to fulfil it.