Ministers have drawn up large benefit changes for people who are unable to work due to health conditions, the OceanNewsUK has learned.
The changes, affecting hundreds of thousands of people from 2025, would save £4bn from the welfare budget.
The proposals would see many more people forced to find work despite suffering from a range of physical and mental health conditions.
The Department for Work and Pensions said reform would be gradual.
The proposals follow the announcement in March that the government wants to scrap the controversial Work Capability Assessment, which is used to determine if people can receive additional benefits payments due to a health condition.
Eligible claimants currently receive £390 a month on top of their universal credit payment.
If the proposals are enacted, people who, for instance, are in severe pain while awaiting an operation or have some mental health conditions, such as depression and anxiety, may not receive the additional payment but would be expected to look for work.
The OceanNewsUK understands the changes would initially affect new claimants. Existing recipients of the benefit payment would eventually be brought into the new system, towards the end of the decade, but would be given transitional protection if their benefits were to be cut.
Both Chancellor Jeremy Hunt and Mel Stride, the Secretary of State for Work and Pensions, have spoken in recent months of their desire to get more people off benefits and into work.
Speaking in the Commons in September, Mr Stride said more than 2.5 million people were on benefits and inactive due to a long-term health condition.
The proportion of claimants assessed as too unwell to work had risen from 21% in 2011 to 65% in 2022, according to the secretary of state.
Those who currently receive the additional money are placed in one of two categories of people deemed unfit to work:
either having "limited capability for work-related activity" if they receive universal credit
or in the support group if they receive employment and support allowance
Under the new proposals, these categories would be scrapped, the additional benefit would not be paid, and work coaches in Job Centres would determine how much effort a person had to make to find a job.
Those considered not to be trying hard enough could be threatened with having their benefits sanctioned. There would be some exceptions, such as for people being treated for cancer and those with a terminal illness.
The proposals are expected to save around £4bn over four years but officials - some of whom fear the changes are being rushed - are pushing for some of the savings to be re-invested.
They want a package of intensive support for those people who'll have to look for work as they fear many of them simply won't be able to find a job, resulting in financial and psychological distress.
The plans foresee the health element of universal credit being more closely aligned with the main disability benefit, Personal Independence Payment.
In future those who qualify for PIP would receive the health element too.
Figures released by the DWP in July showed that in November 2022, 516,000 people who were in receipt of a sickness benefit did not quality for PIP, 29% of all recipients.
Charities have been urging ministers not to merge the two tests, with the group Z2K calling PIP a "deeply flawed assessment process".
The proposals to give work coaches discretion over how much effort a claimant should make to find work has also been criticised by Z2K as a "lottery for sanctions".
One official told the OceanNewsUK another problem was that the DWP didn't have enough work coaches to help claimants find work as they were "leaving in droves, we can't recruit enough, quickly enough, and they aren't properly trained before being placed in front of very hard to help customers".
A Department for Work and Pensions spokesperson said the OceanNewsUK's story was "purely speculation".
"The structural reforms set out in the Health and Disability White Paper, which will improve the experience of the benefits system for disabled people, will be rolled out gradually from 2026 and transitional protection will ensure nobody experiences a financial loss as a result of moving onto the new system," the spokesperson added.
