Sick notes are to be replaced with "fit notes" in a bid to cut down the £100bn cost to the economy of workers' ill-health, the Government announced today.

The system of doctors giving workers a sick note if they are ill has not changed since the NHS was created in 1948.

Ministers said that, under plans to "significantly reduce" ill-health at work, doctors will instead issue fit notes which will specify what workers are able to do.

Trials are being held to replace the paper sick notes with electronic fit notes and the changes are expected to be made by 2010.

James Purnell, Work and Pensions Secretary, said the aim was part of moves to give more help to workers and to intervene as early as possible.

"Everyone has the right to work and we want to design a fair system which supports people so they can work when they are able," said Mr Purnell.

Alan Johnson, Health Secretary, said: "Sick leave costs an estimated £100bn per year, but helping people stay in work does not just have an economic imperative, it has a moral and social one too."

The government also announced a number of other measures today including a review of the health of NHS workers in a bid to improve their wellbeing.

The ministers said the package, which will cost £45m over three years, would support disabled people, or those who became ill, to return to or stay in work by helping them manage their condition and get help to keep their jobs.

A national centre for health and well-being will be created, a health helpline will be launched for small firms and employment advisers will be attached to GP surgeries.

Mr Purnell said the idea was to encourage a "fundamental culture change", adding that in the current economic downturn it was more important than ever to help people stay in work.

No specific targets for reducing sickness absence will be set, although the Government is aiming to cut the number of incapacity benefit claimants by a million by 2015.

Mr Johnson pointed out that half the 600,000 people who move on to incapacity benefits every year had previously been in work, a figure he hoped would be reduced.

The Government was responding to recommendations made earlier this year by Dame Carol Black, who said today: "I believe the measures unveiled by the Government will help make our society a healthier and happier one, where everyone recognises the link between good health and good work.

"But to ensure it happens we need to work together to change attitudes and behaviours. The Government has taken this first important step, but we need to work in partnership, with business leaders, employers and individuals all having a role to play.

"This agenda is vitally important in the current economic climate and we can't afford to neglect it. There are stark economic and social costs if we don't strive to help people be healthy and in work."

Around 172 million working days were lost last year due to sickness absence.

TUC general secretary Brendan Barber said: "This goes some way towards addressing the health problems faced by people at work, and by those unable to work because of ill-health, but it could have gone much further.

"Workers made ill by their jobs need early access to rehabilitation and better support to help them get back to work as soon as they are able to. While the fit for work pilots go some way towards achieving this, they will have little relevance to the vast majority of workers who fall ill or are injured through work.

"More must be done to stop employees from becoming ill or injured in the first place. This report shows that ministers recognise the importance of enforcement in improving health and safety in workplaces. But without additional resources to the Health and Safety Executive and local councils, there is unlikely to be any increase in the number of inspectors."

Paul Kenny, leader of the GMB union said the Government should put the measures on the back burner and concentrate on tackling the recession.

Professor Sayeed Khan, chief medical adviser of the Engineering Employers Federation, said: "Today's proposals represent a major step forward in tackling unnecessary sickness absence, getting people back to work and promoting a culture change so that people recognise work is actually good for them and their families.

"Employers, employees and the UK economy have substantial benefits to gain from a positive approach to occupational health. Too often there is an emphasis on what the employee cannot do rather than what they can do.

"This system should help us tackle sickness absence in a positive manner by enabling employees to return in a role that suits both the employer and employee.

"The burden felt by many doctors relating to sick notes may also be improved with a drive to use a streamlined electronic system to improve communication between employer, employee and GP."