The Conservatives have revealed details of a plan to replace a multibillion pound central repository of NHS patient records with alternatives including online products from Google and Microsoft.

David Cameron has criticised the National Programme for IT, the £12 billion (US$19.9 billion) plan to allow the electronic transfer and management of patient records and appointments.

The Tories say buying "off the shelf" systems, instead of developing custom built-systems would mean that their personalised records system could be delivered at "little or no cost to the taxpayer".

The proposals have been drawn up following a Tory-funded a year-long review into NHS IT systems, chaired by Dr Glyn Hayes, a GP and former chairman of the BCS.

The likely findings of the review have become clear in recent months as the Tories made calls to overhaul the current £12.7 billion National Programme for IT, which has faced repeated accusations of delay and inefficiency.

The NPfIT programme, which is running years behind schedule, will see government-held patient records held in a central national database. But the review proposes that patient records be made available on the internet to patients and doctors.

Dr Glyn Hayes, BCS chair of the report, said: "The review makes clear that NHS IT will only succeed in improving patient care if information is held locally and centred on the patient."

The Conservatives also said they would "halt and renegotiate" contracts with the lead IT suppliers, BT and CSC, "to prevent further inefficiencies"

The proposal could see an incoming Conservative government entangled in lengthy and expensive legal disputes and potential compensation with CSC and BT. The Financial Times said ending these current contracts could run into "hundreds of millions of pounds, if not a billion pounds or more."

Stephen O'Brien, shadow health minister, said more interoperable systems would be made available to NHS trusts, and that the party would encourage the use of open source.

Additionally, patients would be able to update and check their details online, he said.

"You want to have your data held locally and that should be with the person you trust most in the health service, which will be your GP," he told the BBC.

"If we hold the data locally it's more likely to be protected than within this massive database."

But the government immediately rejected the Conservative claims that the alternative plan would work better, questioning the confidentiality of storing the information with Google or Microsoft.

"The Tories need to make it very clear how their plans will ensure patient confidentiality," Ann Keen, health minister, said.

Patients will be able to access their care records through the NHS Healthspace website, she said, without needing to host the information in that way.

A spokesperson at the Department of Health added the NPfIT was delivering in other areas, including patients booking appointments on Choose and Book, new digital x-rays and the rollout of electronic prescriptions.

And last week, former Conservative shadow home secretary David Davis heavily criticised the party's plans, saying it would be "mad" from a security point of view to hand over patient health records to Microsoft or Google.