Tens of thousands of public sector jobs could be lost in the coming years, according to a leading think tank.

The Scottish ITEM Club, sponsored by Ernst & Young, has downgraded its growth forecast for Scotland as world events, rising commodity prices and inflation impact on consumers' confidence and spending.

The group expects public sector employment to be more than 5% lower by mid-2012 than at its 2008 peak, representing a loss of around 40,000 jobs.

It believes the "attrition rate" of public sector employment will continue until 2015 when Scotland will have 80,000 fewer jobs in the sector than in 2008.

But the report said there was also scope for 100,000 jobs to be created in the private sector in Scotland by 2015, up 8% on current levels.

It would see private sector employment pass its 2008 peak in late 2013 or early 2014, by which time the sector will employ half of Scotland's workers, the report added.

Dougie Adams, senior economic advisor to the Scottish ITEM Club, said: "While this is clearly a big hit to total employment levels, a third of those losses may already be behind us and the private sector is creating jobs again, which means that the adjustment may not be as wrenching as some fear.

"The country's labour market has suffered disproportionately over the course of the crisis. On some measures, Scotland could have accounted for nearly a quarter of jobs lost in the UK. That's a staggering figure when you consider we have an 8% share of the population.

"Employment has rebounded by more than 2% since the low point of March 2010."

In its latest update, published on Monday, Scottish ITEM predicted economic expansion of 1.7% this year for Scotland, increasing to 1.9% in 2012 - a respective 0.5% and 0.3% decrease on previously forecast figures in the think tank's November report.

It follows similar downgrades to growth forecasts for the rest of the UK, which is expected to grow by 1.9% this year, rising to 2.4% in 2012.

Mr Adams said: "Scotland's economic output will not match pre-crisis levels until the second half of next year, with above-trend growth unlikely before 2013.

"This setback can be attributed to the squeeze on households, which is proving to be greater than anticipated.

"The upward pressure on commodity prices, reinforced by Middle East tensions and the recent series of natural disasters, has hit consumer inflation figures with a vengeance."

He said there was scope for the forecast to change but the factors meant Scotland's recovery is now "almost completely dependent" on business investment.

Hywel Ball, Ernst & Young's senior partner in Scotland, said: "There is little prospect of a consumer-led recovery.

"Scotland is relying on those companies that shifted their focus from spending to building their cash resources to channel that money back into the economy, particularly through buying from smaller companies that survive on business-to-business spending."

A spokesman for the Scottish Government said: "This report provides further evidence of the urgent need for an economic Plan B or flexibility from the UK Government in order to strengthen recovery and employment.

"The Scottish Government is working hard to create jobs, with the latest labour market statistics showing that unemployment levels declined by 10,000 during the three-month period February-April 2011 - the seventh consecutive reported fall.

"Scotland's employment rate is higher than for the UK as a whole and our economic inactivity rate remains lower than the UK rate."

The think tank uses the same economic model for its forecasts as the UK Government's Treasury uses for its policy analysis and Budget forecasts.