By Mary Gahan BBC News Online reporter at the CBI conference

The head of the UK's biggest public service union has told business leaders that there is a role for private companies to help modernise hospitals and other public services.

Dave Prentis, the general secretary of Unison, told the CBI's annual conference:

"We are not anti-business. Private enterprises and public services cannot be seen as alternatives, they are inextricably linked."

But he made it clear that he did not believe the private sector was the only solution.

'No quick-fix solutions'

Public-private deals are an important part of the government's agenda and are being used to build schools and hospitals and modernise public services.

Unions have been calling for the whole system to be reviewed, and Mr Prentis renewed that call.

"There should be a review of the PFI (Public Finance Initiative). What's so wrong with that? It's only about being prudent."

Mr Prentis said it was clear that reform was needed but he warned against quick-fix solutions.

At the Labour Party conference, the unions defeated the government on their call for a moratorium on PFI projects pending such a review.

But the government has made it clear it that it would continue to roll-out such projects, which it considers vital if it is to build more schools and hospitals.

Changing the tone

The CBI launched its own document spelling out objectives and obligations for private companies delivering public services.

Rod Aldridge, chairman of Capita Group, told bosses that they must understand and respect the concept of a public service ethos.

He said the CBI rejected the notion of "private good, public bad" and called for the tone of debate to change.

He admitted there had been problems: "I do accept that not every PPP has worked perfectly from the outset.

"But it's important to work on it and refine it rather than criticise it from the outset."

Many companies are becoming reluctant to bid for PPP projects, fearing the high cost of bids and the long delays before projects begin.

Warning over pay disputes

The CBI wants to work together with government and trades unions to speed up the process.

Health Secretary Alan Milburn said that PPPs were making a difference to the national health service.

"Despite what its sometimes vocal opponents say, PFI is a partnership that works."

But there was a warning for Mr Milburn and his fellow ministers about the firefighters' strike and other disputes.

Mr Prentis said: "If anybody in the government actually thinks that the wave of disputes in the public services now is just about pay - it's not.

"It's the outpouring of a workforce that feels undervalued."

Mr Milburn has himself been embroiled in a dispute with hospital consultants - who have rejected his offer of a 19% pay increase in return for changes in their working conditions.