Troubled healthcare software firm iSoft, a major supplier to the government’s crisis-stricken £12.7bn overhaul of the NHS’s IT systems, has suspended its shares and put itself up for sale.

The company has for years struggled to meet agreed delivery targets to replace near-obsolete systems together with its NHS supplier partner Computer Sciences Corporation (CSC).

Virginia-based CSC, listed in New York with a market value of $7.5bn (£4.6bn), is now regarded as the most likely buyer for iSoft given their contractual ties across the Midlands and east and north of England, particularly in relation to the software group’s controversial next-generation Lorenzo platform.

That would make CSC one of the biggest operators of hospital computer systems in the NHS, taking over about 70 acute hospital operations as well as a large part of the community healthcare IT market.

CSC and subcontractor iSoft were set a deadline of this month by which to install Lorenzo at Pennine Acute Hospital Trust before they would receive already delayed milestone payments from the Department of Health.

That deadline has been missed and healthcare officials are refusing to sign a long-awaited contract renegotiation with CSC as a result. CSC is expected to give fuller details of any losses from its work with the NHS following its financial year-end next month.

In 2003 CSC became one of the largest contractors to the NHS’s ambitious IT programme, which was set in train under Tony Blair and is said to be the largest non-military IT project in the world. The US firm has three long-term regional contracts, each worth £1bn, but each has had major problems, some of which have been blamed on delays in software development by iSoft.

The Australian software company was previously called IBA Healthcare, but changed its name after it acquired failing UK firm iSoft in 2007. The latest iSoft incarnation today requested that its shares be suspended on the Australian stock exchange.