iSoft, a lead supplier of software to the government's £6bn programme to overhaul the health service, is facing parliamentary scrutiny over its accounting policies.

Paul Farrelly, the Labour MP for Newcastle under Lyme and vice chair of the new all party parliamentary group on corporate governance, has tabled a number of questions about iSoft and the National Programme for Information Technology (NPfIT) which has oversight of the £6bn investment to modernise healthcare in Britain by linking every NHS site electronically. "iSoft is an important supplier of IT services to the NHS' NPfIT. I have asked a number of questions of the government regarding the processes it goes through to vet companies involved in such crucial projects," Mr Farrelly said.

One question asks: "If the Department will ask Accenture to report on the a) financial standing and b) the accounting treatment of revenues and profits at iSoft."

Accenture is one of the prime Local Service Providers contracted by the NPfIT to implement the electronic care records service in northeast and east England. Accenture has selected iSoft's care records technology to be one of the cornerstones of the project.

Mr Farrelly, a former financial journalist, has also quizzed the department over the steps it has taken to check the financial viability of contractors and sub-contractors generally. Last night Isoft was quick to respond to Mr Far relly's probing. "We have a very open relationship with Accenture and have always shared detailed commercial information, and we will continue to do so," a spokesman said. "The National Programme has been very thorough in scrutinising the capability of all its providers."

"For the record, I can categorically confirm that there are no issues with Isoft's accounting policies, nor with its financial viability."

The parliamentary questions have been tabled amid attempts by iSoft to stop dissemination of a review of its financial performance and ac counting policies compiled by accountants Deloitte Touche ahead of last year's merger with rival Torex. The report was compiled for directors of Torex, who later indicated that they were happy with iSoft's financial condition by proceeding with the merger.

This £700m deal - controversial at the time because of competition concerns - was inspired by the ambition of both businesses to increase their critical mass and improve access to the government's technology spending bonanza, which promises to modernise healthcare in Britain by linking every NHS site electronically. In one letter to the Guardian, referring to the Deloitte report, iSoft alleges that the Guardian has confidential information and documents in its possession, and demands that the newspaper hands over any notes or documents.

"In particular you clearly have in your possession all or part of a report prepared by Deloitte for Torex as part of due diligence for the merger with Isoft," the letter states, before adding: "If...you fail to recognise your obligations in relation to confidential information then our clients will take action to restrain you, and the Guardian, for misuse of that information."

In an attempt to clarify the matter, the Guardian has tabled a number of questions to iSoft, mainly of a technical nature. The company has declined to answer most of these, citing the confidential nature of the information.

The company insists that the information has been taken out of context and it cites the fact that Torex went ahead with the deal as evidence that its accounting methods and business model are beyond criticism. However it refuses to answer any questions that it says might be linked to the Deloitte report. Independent accountants routinely prepare due diligence reviews, such as the Deloitte report, ahead of virtually all mergers and takeovers. This work would normally focus on accounting policies, such as how income is treated in the company's books or how the firm handles its liabilities.

Since British accounting standards are "principle-based" as opposed to the "rule-based" system used in America, differing opinions on accounting treatments often surface during mergers. Due diligence reports provide one means of debating these.