The Opposition says the State Government should take responsibility for a downgrade to Queensland's credit rating by a major international ratings agency.

Fitch says Queensland's fiscal position and debt matrix have deteriorated over the past four years and a recovery is not expected for at least another two years.

The ratings agency has downgraded Queensland's credit rating from AA+ to AA with a stable outlook.

The announcement came just two days after the Liberal National Party (LNP) Government handed down its first state budget.

Treasurer Tim Nicholls says the move shows the former Labor government's financial management was appalling.

"Of course we're disappointed in what's happened as a result of the actions of the former government in the lead-up to the March 24 election," he said.

"The warning clearly is you cannot continue down the path of debt and deficits."

Mr Nicholls says the LNP have known since June a downgrade was imminent.

He says Queensland's debt more than doubled in the past three years under Labor.

Mr Nicholls says the savings outlined in the LNP's budget are to thank for the stable outlook.

"They acknowledged the strong fiscal measured that we are taking and they are stable at this stage because of the expenditure measures announced in the budget three days ago," he said.

Mr Nicholls says the current LNP government is not to blame.

"This is really a hangover though of the financial debt and deficit that was bequeathed to Queensland by the Labor government," he said.

"We take full responsibility for the decisions that we've made in the budget, we take full responsibility to fix up the mess that we were left.

"But it is equally important to remind people that the mess that we are clearning up was made by Labor, that the debt that is being incurred was already being incurred by Labor."

'Unfair'

Opposition treasury spokesman Curtis Pitt says that is unfair.

"They now own the economy of Queensland - they've got to take that responsibility in full," he said.

"The Newman Government has been blaming Labor since day one - this is about responsibility."

"This is about what has happened since the election.

"They were put on notice in March and they were going to be watched very closely in terms of how they presented their budget and how they took the state's fiscal direction forward - that's what Fitch has said."

Fitch says Queensland's credit rating could be further downgraded, if its fiscal position does not improve or stabilise over the next two to three years.

The company says it expects Queensland to return to a positive operating balance by 2015 and is encouraged by the latest state budget.

The other major agencies, Moody's and Standard & Poors, have kept their credit ratings for Queensland unchanged.

'Surprise'

But economist Saul Eslake says the downgrade by Fitch is not the end of the world for the State Government's finances.

"In a sense the markets have already made their own assessment of Queensland's financial position over recent years," he said.

"In practice I doubt that this announcement by Fitch will materially change that, unless the markets come either to believe that the other two rating agencies follow Finch or if they come to doubt some of the financial projections that were made in this week's Queensland state budget."

Fitch says Tuesday's state budget outlines strong measures to restore Queensland's financial position through significant cost reductions and raising revenue.

Mr Eslake says given this acknowledgement, he is surprised by the timing of Fitch's downgrade.

"I'm not sure what else they could have expected this Government to have done," he said.

"Maybe the point is that no Government in their mind could have prevented a downgrading of their assessment of Queensland's credit worthiness.

"As I say the other rating agencies don't appear to have come to the same judgement and nor have the financial markets in terms of the way that they are pricing Queensland's debt."