Forces say they face a series of new demands

Senior officers said that debts would continue to rise unless new money was made available to keep pace with the raft of new legislation.

It has been predicted that by next year forces could be in deficit by �8m.

But the justice minister flatly denied the claims and said a recent review had judged four forces to be over-funded.

Leading officers also expressed concern about funding new retirement proposals with the number of officers ending their careers this way expected to peak in four years' time.

'Stretched resources'

Putting their case to Holyrood's two justice committees on Wednesday, the Association of Chief Police Officers in Scotland (Acpos) said new money was essential to maintaining services.

It said: "The police service in Scotland continues to meet the challenge of enforcing new legislation, however the pace of legislative change coupled with insufficient additional resources places a great strain on the already stretched resources."

On the issue of new anti-terrorism measures, Acpos said: "It is essential funding is on a par with England and Wales if an effective and co-ordinated approach to terrorism is to be achieved."

Like all public services, the police must look to carry out their business more efficiently and more effectively Cathy Jamieson Justice Minister

But Justice Minister Cathy Jamieson said the Scottish police service was not �8m short and that a funding review agreed by Acpos last year judged four forces to be over-funded, while the other four needed more resources.

Ms Jamieson said the police had to do more to identify efficiencies which could be ploughed back into frontline services.

"Of course tackling terrorism and dealing with anti-social behaviour are significant challenges," she said.

"But like all public services, the police must look to carry out their business more efficiently and more effectively.

"That's also a big challenge for Scotland's police chiefs - to match the commitment we have made to them in terms of investment with real improvements in the way they use that money."

But Acpos defended their record on efficiencies and said savings in Scottish police forces had risen by 114% from �7m in 2003-04 to �15m in 2004-05.

Retirement issue

Officers said: "Forces are already achieving cash and time releasing efficiency savings to ensure service levels are maintained in the face of a funding shortfall within the current financial year."

Appearing before MSPs, senior officers said additional funding was also needed for more costly pension arrangements, with a peak in retirements in 2009-10.

Ms Jamieson said the retirement issue would be tackled with new recruits and that hundreds of officers had been freed up by the contracting out of prison escort services.

Representatives of the Association of Scottish Police Superintendents and the Scottish Police Federation also appeared before MSPs.

We will be able to use these efficiency savings but they are not for growth Joe Grant Scottish Police Federation

Joe Grant, general secretary of the Scottish Police Federation, said there had been no real growth in the police budgets for a number of years.

He said: "We will be able to use these efficiency savings but they are not for growth, they are quite simply to continue to do what we are currently doing."

"I don't think that's good enough for the public."

Ms Jamieson said overall investment in Scotland's police service had risen by more than twice the rate of inflation since 1999.

She added that last year, a further 17% increase was announced over the next three years.