GP fit notes declaring people unable to work will be replaced with support to help them stay in their job, under a government pilot scheme.
GPs in two areas of England will refer patients for support alongside fit notes, while two others will stop issuing fit notes entirely.
The government said the current system was "broken", with too many people signed off work with no help for them to return.
The move is part of efforts to tackle the growing number of people who are out of work due to poor health.
There is concern about the impact this has on the economy, as well as contributing to increased benefit payments and pressure on the NHS.
More than 11 million fit notes are issued every year, with the numbers increasing since the Covid pandemic.
Fit notes are approved when someone is unwell or cannot work for more than seven days.
They advise on how the patients' health problems impact on their ability to work - and can help to access certain benefits and sick pay.
A patient can be declared "not fit for work" or "maybe fit for work" with some adjustments, but the government says more than nine-in-10 sign people off work entirely.
Earlier this year, hundreds of GPs told the BBC they had never refused to sign a patient off work for mental health issues.
Many also raised concerns that issuing fit notes should not be part of a GP's job.
The four pilot schemes, lasting up to a year, cover up to 100,000 appointments and are backed by £3m of funding.
They aim to test different approaches to find the best way of tackling the increase in fit notes.
In Birmingham and Solihull, as well as Coventry and Warwickshire, GPs will initially issue a fit note where needed but patients will also be referred to support services.
In Cornwall and the Isles of Scilly, along with Lancashire and South Cumbria, GPs will refer patients directly to support services, without issuing a fit note.
The pilots will test whether support should be led by healthcare professionals or non-clinical staff, such as work coaches and social prescribers, where community groups or activities are recommended to patients to improve their health.
They will also involve conversations with employers about adjustments to help people return to work.
The pilots will be delivered through existing NHS WorkWell sites, which connect patients with services such as physiotherapy and counselling.
It comes after a review earlier this year on how to get people back into work recommended a new approach to fit notes.
The review, led by former John Lewis chairman Sir Charlie Mayfield, found the system was "not working as intended", with most GPs lacking the training and time to assess someone's ability to work.
It also found fit notes were often a barrier to contact between employers and employees.
Work and Pensions Secretary Pat McFadden said: "Fit notes are too often a dead end - a piece of paper that tells people they can't work but does nothing to help them get better.
"We're changing that. By bringing employers, the NHS, and patients together we can help people recover faster, stay connected to their jobs, and get the economy firing on all cylinders."
Prof Victoria Tzortziou Brown, president of the Royal College of GPs, said "the current system can involve significant administrative work that takes time away from patient care".
She added: "However, any reform of the fit note process must put the health and wellbeing of patients first, be fully resourced and avoid creating additional workload for general practice."
John Foster, from the Confederation of British Industry, which represents businesses, welcomed the pilot, saying the current system "fails employers, workers, and the economy".
Tom Pollard, from the mental health charity Mind, said: "Giving people the chance to have detailed conversations about the challenges they face and the support they need is a positive step.
"However, it's vitally important that this is a supportive and collaborative process.
"People with mental health problems must not feel pressured to work when they don't feel able, or to return to workplaces that are not supporting their mental health."
Conservative shadow health secretary Stuart Andrew said it was "good to see Labour finally waking up to fit note reform".
"The Conservatives have long argued that too many people are being written off work when they could be supported to recover, stay independent and contribute," he said.
The government has been grappling with a ballooning benefits bill, as increasing numbers of people are out of work, driven by a surge in mental health issues among young people and muscular skeletal issues in older age groups.
Last year, in the face of a rebellion by Labour MPs, the government dropped major changes to the welfare system, including restricting eligibility for disability benefits, which it had hoped would save £5bn a year.
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