Liz Kendall, the welfare secretary, has faced down angry Labour MPs to unveil drastic cuts to the UK’s benefits system that will leave many sick and disabled claimants worse off.

The measures, which the government argues are needed to “fix the broken benefits system” and balance the nation’s books, are expected to cut £5bn from the benefits bill by the end of the decade.

The work and pensions secretary announced to MPs on Tuesday that as part of the package her department would spend up to £1bn a year extra on helping people back into jobs, with plans ranging from supportive calls to intensive training programmes.

But Labour MPs have voiced deep concerns over the cuts, under which only the most severely disabled will be able to claim personal independent payments (Pips), the key disability benefit that is not linked to work.

The government is on course for a parliamentary showdown with its own backbenchers as Kendall confirmed there would have to be votes on the changes to Pips and universal credit, and angry MPs threatening to vote against.

Debbie Abrahams, Labour chair of the Commons’ work and pensions committee, warned against “balancing the books on the backs of sick and disabled people”.

She called on the government to publish the equality impact assessment and poverty analysis, which will both set out the detailed impact of the cuts, before the spring statement.

John McDonnell, former Labour shadow chancellor, said the plans would lead to “immense suffering” and ultimately, as seen in the past, potentially to the deaths of some of the most vulnerable people.

Clive Lewis, the Labour MP for Norwich South, warned the changes would cause “pain and difficulty” for millions of constituents who were on the brink.

“I would like her department to be able to look my constituents in the eye … to tell them this is going to work for them,” he said. “My constituents, my friends, my family are very angry about this and they do not think this is the kind of action a Labour government takes.”

Under plans set out in the green paper, published alongside Kendall’s statement, eligibility criteria for Pips will be tightened so that people will need to score four points in at least one activity to qualify for the daily living allowance.

The government will consult on frequent reassessments of Pip claimants, although the most severely disabled are expected not to have to be reassessed. The unpopular workplace capability assessment will be scrapped by 2028.

The basic rate of universal credit for those looking for, or in, work will rise by about £15 a week from April 2026, but the incapacity benefit will be cut for new claimants judged as unfit for work. Support will be frozen for existing claimants, with an additional premium for those with severe lifelong conditions meaning they will never work.

People under the age of 22 wanting the health top-up of universal credit will no longer qualify under plans being consulted on, with the savings being reinvested in work and training schemes to help get them back into the workplace.

There will also be a new “right to work” scheme for those on incapacity benefits so they can try to return to work without risking losing their entitlements. “I’m not interested in being tough, I’m interested in real people and their lives,” Kendall said.

The welfare secretary told MPs the benefits system was “failing the very people it is supposed to help and holding our country back”, with one in 10 working age people now claiming sickness or disability benefit and almost 1 million young people not in education, employment or training.

A total of 3.66 million claimants in England and Wales were entitled to Pips as of 31 January, according to new figures published by the Department for Work and Pensions. This is up 12% from 3.27 million a year earlier. At the end of January 2020, before the start of the Covid pandemic, the figure stood at 2.14 million.

She said that spending on working-age sickness and disability benefits was up £20bn since the pandemic, and set to rise by a further £18bn by the end of this parliament, to £70bn a year.

But she added: “There will always be people who can never work because of the severity of their disability or illness. Under this government, the social security system will always be there for people in genuine need. That is a principle we will never compromise on.

“But disabled people and people with health conditions who can work should have the same rights, choices and chances to work as everybody else.”

James Taylor, of the disability equality charity Scope, said: “The biggest cuts to disability benefits on record should shame the government to its core. They are choosing to penalise some of the poorest people in our society. Almost half of families in poverty include someone who is disabled.

“Life costs more if you are disabled. Ripping £5bn out of the system by 2030 will be a catastrophe for disabled peoples’ living standards and independence. The government will be picking up the pieces in other parts of the system with pressure on an already overwhelmed NHS and social care, as more disabled people are pushed into poverty.”

Sarah Hughes, chief executive of mental health charity Mind, said: “Mental health problems are not a choice – but it is a political choice to make it harder for people to access the support they need to live with dignity and independence. These reforms will only serve to deepen the nation’s mental health crisis.”

The Disability Benefits Consortium, an umbrella body representing more than 100 charities and organisations, condemned the “cruel cuts”. The organisation’s policy co-chairman Charles Gillies said: “These immoral and devastating benefits cuts will push more disabled people into poverty, and worsen people’s health.”