Troubled medical software firm iSoft is facing a fresh investigation into possible accounting irregularities.

But renewed bid interest could be emerging around a second struggling software firm, Misys.

The Accountancy Investigation and Discipline Board said yesterday it would question former iSoft directors and auditor RSM Robson Rhodes over financial statements the company issued between 2003 and 2005.

If the inquiry uncovers any wrongdoing, a tribunal will be held which could impose unlimited fines or strip chartered accountants of their qualifications.

Manchester-based iSoft, which closed its office on Aston Science Park nearly a year ago, is already under investigation from the Financial Services Authority over alleged misleading statements to the stock market.

ISoft said the AIDB investigation was likely to cover similar matters to that by the FSA, adding it would cooperate with the probe.

Robson Rhodes also said it would fully cooperate with the AIDB.

"We wish to emphasise that we are not aware of any allegations against the firm," David Maxwell, managing partner at Robson Rhodes, said.

ISoft has been damaged by the fall-out from well-publicised delays to the NHS software upgrade project and has lost 90 per cent of its stock market value in little over a year.

Last week it put itself up for sale, saying it was prepared to enter talks with potential bidders.

The AIDB and FSA inquiries come after an internal investigation at iSoft found evidence of financial irregularities.

It added: "The initial independent investigation into possible accounting irregularities conducted by the company’s current auditors, Deloitte & Touche, in July did not uncover evidence that any of the current non-executive directors had any knowledge of any irregularities."

ISoft has suspended commercial director Steve Graham. One other employee has also been put on special leave of absence.

The company has been plagued by problems since taking on contracts as part of the #6.2 billion IT modernisation programme at the NHS.

The project has been hit by severe delays – with some of the blame laid at iSoft’s door – and fears that the central computer system will not be used as widely as was once thought.

Isoft shares closed 1p at 47.25.

Hopes that Evesham-based Misys could become a target picked up after the announcement that ValueAct Capital, where incoming chief executive Mike Lawrie was once employed, had acquired a 4.4 per cent stake.