The potential savings from the £12.4bn NHS IT project in England have been hit by delays dogging key parts of the programme, the government admits.
The NHS IT project is a 10-year project
Officials said a prudent estimate from data from a fifth of NHS trusts showed it was on course to save £1.14bn.
They said the figures were positive but acknowledged it could have been more.
The Tories said the savings were peanuts compared to the scale of the project - it is the biggest civilian IT scheme in the world.
Central parts of the 10-year programme - aimed at linking more than 30,000 GPs to nearly 300 hospitals by 2014 - have been running up to two years behind schedule.
Electronic medical records and "choose and book" - an online appointments system for GPs - have been the worst-hit.
Despite the problems, the government said £208m had been saved by March 2007, mainly because of the broadband network installed across the NHS and the progress made with the digital imaging and scanning.
And it predicted that by the end, the savings would top £1bn.
The figures were revealed in the government's benefits statement for the National Programme for IT.
Ministers were told to publish the accounts by the House of Commons' Public Accounts Committee in a report last year criticising the progress being made.
The document shows that the project has under-spent by over 40% so far.
This indicates the scale of the delays as suppliers are only paid when they deliver, although officials warned this could not be interpreted as exactly over 40% of project falling behind schedule.
Richard Jeavons, a senior IT official at the Department of Health, said: "We can be positive about the evidence emerging.
"Of course, if we had not had delays we would be further ahead."
And Health Minister Ben Bradshaw said there were also real benefits for patients that could not be costed, including staff having quicker access to their records.
He added: "Our use of computer technology in the NHS is becoming the envy of the world."
But shadow health minister Stephen O'Brien criticised the fact only £208m had been saved so far, calling it "peanuts" compared to the cost of the programme.
"It is certainly nothing the government should be crowing about as it is the very least they should be doing to recover their incompetence on a grand scale."