Sickness benefits claimants will no longer have to go through reassessments to keep their payments if they suffer from chronic illnesses, the Work and Pensions Secretary is to announce.

Employment Support Allowance (ESA) will continue automatically for those who have lifelong, severe health conditions with no prospect of improvement, Damian Green said.

The testing process, which includes reassessing conditions every six months, has come under intense criticism for failing some of the most seriously ill and disabled.

But the reforms will help end the anxiety and financial insecurity that claimants may have felt, Mr Green, who will unveil the plans at the Conservative party conference, said.

The criteria will be drawn up with health professionals but illnesses such as severe Huntingdon's, autism or a congenital heart condition, are among those that are likely to qualify for continuous payments without reassessment.

Mr Green said: "We are building a country that works for everyone - not just the privileged few. A key part of that is making sure that all those who are able to work are given the support and the opportunity to do so. But it also means ensuring that we give full and proper support to those who can't.

"That includes sweeping away any unnecessary stress and bureaucracy - particularly for the most vulnerable in society.

"If someone has a disease which can only get worse then it doesn't make sense to ask them to turn up for repeated appointments. If their condition is not going to improve, it is not right to ask them to be tested time after time. So we will stop it."

Mr Green said the change was being made because it was "pointless" to repeatedly test claimants who are not going to get better.

He told BBC Radio 4's Today programme: "I believe in a welfare state where you have got to be hard-headed, but you shouldn't be hard-hearted.

"We want the welfare state to work for everyone, just as we want the economy to work for everyone, and there are a group of people for whom constant reassessment is pointless and which does increase their stress and anxiety levels."

Mr Green said it would be a "retrograde" move to scrap the tests for all ESA claimants, because for the "vast majority of people, work actually helps them".

Michelle Mitchell, chief executive of the MS Society, said: "This is a victory for common sense. Frequent reassessments for people with progressive conditions like MS are too often a waste of time and money; they can leave people with uncertainty and fear of having their support taken away.

"We are therefore delighted that the Government have listened to our concerns and have agreed to stop reassessments - albeit for only some ESA claimants.

"This is good news, but there's still a lot more to do for people with MS - including improving the assessment for ESA and calling for inappropriate reassessments to stop for other vital benefits, like PIP."

Mark Atkinson, chief executive at disability charity Scope, said: "In the short term this will be a welcome change for some disabled people, and it's good to see the Government recognising that the work capability assessment needs wider reform.

"We'd like to see Government going much further and starting a consultation with disabled people on the wholesale reform of the fitness-for-work test.

"Disabled people are pushing hard to get jobs, but still face many barriers to find work and thrive in employment. The test should be the first step to identifying those barriers so the right support can be put in place to help people get back to work."