Tax rises in the Budget will not be the last, the Chancellor has suggested after admitting that the money she will give the NHS on Wednesday will not be enough to fix it.

Rachel Reeves is set to inflict a £35 billion tax raid by raising National Insurance contributions for employers and increasing capital gains tax, in part to fund new NHS technology and hospital rebuilding programmes.

However, on Monday she said billions more for the NHS in the Budget would not undo what she called “14 years of damage” to the health service under the Conservatives – raising the prospect of further rises in years to come.

Wes Streeting, the Health Secretary, said this year’s funding could only “arrest the decline in the NHS and start fixing the foundations”, despite an increase to the capital budget to its highest level since 2010 and pay rises for staff.

Mr Streeting said he could not even give a commitment that the NHS would avoid needless deaths or a winter crisis with the increased funding. “I can’t promise that there won’t be people waiting on trolleys in corridors this winter,” he added, saying the Government could not “wave a magic wand” to make problems disappear.

On Monday, Sir Keir Starmer said he could not continue “the fiction” that “you can always have lower taxes and that your public services will run properly”. Instead, the Prime Minister said he intended to deal with “the tough stuff” this week and could not give “a cast iron guarantee” that there would not be more pain to come in the years ahead.

On Tuesday, ministers will announce £1.5 billion in NHS funding for surgical hubs, scanners and radiotherapy machines in order to deliver the Labour manifesto commitment of an extra 40,000 appointments per week within a year.

From this week, teams of medics will be sent to start clearing waiting backlogs, beginning in the areas with the highest levels of worklessness.

On Wednesday, Ms Reeves will announce billions for investment in technology and digital innovations across the health service “to boost productivity and unlock significant savings for the NHS in the long-term”.

More will be spent on shoring up the hospital rebuilding programme and helping plug a £14 billion maintenance backlog, with Mr Streeting describing Boris Johnson’s previous pledge of 40 new hospitals as a “work of fiction”.

Ms Reeves said: “I don’t think, in one Budget, you can undo 14 years of damage.

“But in this Budget we’re going to provide the resource necessary to deliver on our manifesto commitment to 40,000 additional appointments every single week to reduce that huge backlog, as well as the increase in the capital budget to take it to its highest level since 2010 to invest in the new scanners and the radiography equipment.”

Mr Streeting said: “What this Budget will enable us to do is arrest the decline in the NHS and start fixing the foundations so we can not only get the NHS back on its feet but also make sure it’s fit for the future as part of our long-term plan.”

He said “the reckless spending of the previous government” meant that, when he became Health Secretary, he was told the NHS would need to start making cuts, with 20,000 fewer appointments rather than the 40,000 extra Labour had promised.

Asked whether the Government was braced for a crisis across the health service this winter, he said: “We’ve had an annual winter crisis in the NHS for years under the Conservatives, and they managed to turn a winter crisis into a year-round crisis.

“I can’t pretend that we’re going to be able to wave a Labour magic wand and make all of those problems go away this winter. There will still be real problems this winter, but we’re not going to deny the scale of the problems.”

The Royal College of Emergency Medicine has warned that hundreds of people are dying every week because of long waits in A&E.

Asked whether the Government would be able to save people from avoidable deaths this winter, Mr Streeting said: “We will do everything we can to keep patients safe this winter.

“I cannot pretend that the situation we’ve inherited from the Conservatives isn’t dire, and it will take time to turn the situation around.

“And obviously the number one priority for us has got to be patient safety and doing the best we can against the inheritance that we’ve been dealt to keep people safe and well this winter, but also to arrest the decline so we’re not locked in an annual cycle of crisis after crisis which we’ve been subjected to under the Conservatives.”

Dr Ian Higginson, the vice president of the Royal College of Emergency Medicine, said A&E departments were “bursting at the seams”, with long waits on trolleys linked with hundreds of excess deaths every week.

He added: “This Government was elected in July, which should have been ample time to at least start to put in place measures and funding to help reduce these avoidable deaths. So far we have seen words and apparent acceptance of the status quo.

“To talk about prioritising patient safety while allowing dangerous and degrading ‘corridor care’ to continue does not make any sense. Ending this shameful situation must be the priority right now.”

In a speech on Monday, Sir Keir appeared to signal a move to a Scandinavian-style tax burden to continue funding increases for the NHS.

Asked whether his priorities were out of step with the public mood after a poll suggested that most voters would prefer lower taxes to investment in public services, he said: “No. I think, for too long, we pretended that you could lower tax and spend more on your public services, but you can’t – and it’s about time we faced up to that.

“Almost everybody knows the NHS is broken. We’re going to fix it, put it back on his feet, and make it something we can be proud of again. But what we’re not going to do is continue the fiction that got us here in the first place – the pretence that you can always have lower taxes and that your public services will run properly.

“The last 14 years have shown this is completely and utterly untrue, and people voted for change.

“Nobody wants tax rises, least of all me, so we will do the hard work in this Budget to allow us then to rebuild the country. I can’t give you a cast iron guarantee that never again in any Budget will there be any adjustment to tax, because we just don’t know what is round the corner.”

Helen Morgan, the Liberal Democrats’ health and social care spokeswoman, said: “After years of mismanagement by the Conservatives, the NHS is in desperate need of support. Millions are waiting in pain and distress for the care they need.

“It is disappointing that the new Government is not showing the ambition that this country needs to get the NHS back on its feet. If arrested decline is the best they can do, I fear that people will only continue to wait too long for treatment.”