Some Labour backbenchers are “jumping to conclusions” about expected reforms to the welfare system before the plans are confirmed, a Treasury minister has suggested.

Emma Reynolds, the economic secretary to the treasury, urged MPs to be “patient” amid mounting backbench discontent over changes expected in the coming days.

Work and Pensions Secretary Liz Kendall is expected to set out plans for reform on Tuesday in an effort to get more people back to work and cut the cost of a benefits bill described by ministers as “unsustainable”.

Mayor of Greater Manchester Andy Burnham arrives at BBC Broadcasting House to appear on Sunday with Laura Kuenssberg (Aaron Chown/PA)

Andy Burnham has urged “caution on how changes are made”, after an outcry from some Labour MPs over the reforms.

Speaking to BBC Radio 4’s Today programme on Monday, Ms Reynolds said: “We’ll set out further details, but the severely disabled and the most vulnerable will always get support, and there will always be a safety net.

“And some colleagues are jumping to conclusions about our plans before they’ve heard them, so I just urge them to be patient.”

Several backbenchers have expressed frustration to the PA news agency at a lack of communication from ministers, with one describing “engagement sessions” held by Number 10 as a “tickbox exercise” and another saying many of their colleagues had made it clear they would vote against such proposals.

Reports suggest the scale of the backlash has prompted a rethink of rumoured plans to freeze the level of personal independence payment (Pip) rather than increase it in line with inflation, delivering a real-terms cut to 3.6 million claimants.

But other backbenchers have expressed anger that proposals such as the Pip freeze had leaked out, suggesting to PA this had been done in “bad faith” before anything had been agreed by Ms Kendall and the Treasury.

Ms Reynolds suggested that it is “everyday business” for the Government to have discussions with backbenchers around policy.

Asked whether MPs should fall in line, the Treasury minister said: “We have a big majority, we are a Government that secured a mandate for change.

“It is absolutely everyday business that we should have discussions with backbenchers, meetings between our MPs and ministers happen all day, every day. So this isn’t something that is any different, but we’re determined to strike the right balance here.

“We’ve got to reform a system that is failing everybody, and we’ve got to do that according to our values.”

Ministers insist that reform is necessary given the number of people in England and Wales claiming either sickness or disability benefit has soared from 2.8 million to about 4.0 million since 2019.

The benefits bill has risen with this increase, reaching £48 billion in 2023-24, and is forecast to continue rising to £67 billion in 2029-30 – a level that would exceed the current schools budget and which the Government regards as unsustainable.

Health Secretary Wes Streeting outside BBC Broadcasting House in London (Stefan Rousseau/PA)

It comes as mayor of Greater Manchester Mr Burnham urged “caution” on benefit changes.

Writing in The Times, he said that Sir Keir is “right” and “the British state is not sustainable in its current form” but said the Government should focus on helping people into work rather than simply cutting benefits.

He said: “I would share concerns about changing support and eligibility to benefits while leaving the top-down system broadly in place. It would trap too many people in poverty.

“And to be clear: there is no case in any scenario for cutting the support available to disabled people who are unable to work.”

Ms Reynolds said on Monday that there will “always be a safety net for the most vulnerable”.

Although she declined to comment on speculation about what changes could be brought forward, she told Times Radio: “What I will say is that what’s really important here is that there will always be a safety net for the most vulnerable.

“We are the party that created the welfare state back in 1945 and of course, we need a system that is sustainable, and in being more sustainable it will maintain that crucial safety net for the most vulnerable.”

On Sunday, Health Secretary Wes Streeting had suggested there has been “an overdiagnosis” when it comes to mental health conditions.

Asked on LBC whether she agreed with Mr Streeting, Ms Reynolds said: “What we’re trying to grapple with and what Wes was saying is we have many, many people who are signing up for personal independence payments and that seems to be out of kilter with the prevalence of the increase in certain conditions.

“So we need to understand here what’s going on.”