Shadow work and pensions secretary Jon Ashworth accused him of “acting in his own interest” and making a conscious decision to force people into poverty.
The Labour minister warned pensioners were “cutting back on hot meals” and “forgoing hot showers” as they cannot afford the cost.
Mr Ashworth told Sophy Ridge On Sunday on Sky News: “Rishi Sunak absolutely had more room for manoeuvre in this spring statement and mini budget, but rather than acting in the interests of the British people, he was playing games.
“He was acting in his own interest because he thinks by offering an income tax cut in two years that’ll help him politically with Conservative MPs if there’s a leadership contest or that’ll fit the Tory election grid.
“I don’t believe that putting 1.3 million people into poverty because you’re imposing a very severe real-terms cut to universal credit, you’re imposing the biggest cut to the pension in 50 years, is fair.”
The Government will uprate benefits by 3.1 per cent in April although the inflation rate is expected to average nearly 8% over the year.
Mr Ashworth said Mr Sunak should have imposed a “windfall tax” on the profits of oil and gas companies to generate funds to help struggling families and pensioners with energy bills.
He said: “He chose not to do that.
“Instead, he’s imposed these very punishing tax rises, these very severe real-terms cuts to the pension and support like universal credit, and he’s expecting people to be grateful because two years down the road he’s saying there’s going to be an income tax cut even though that income tax cut nowhere near offsets the 15 tax rises that he has imposed on the British people, £3,000 extra per household if you do a rough and ready calculation.
“He is a tax-rising Chancellor, he is Mr Tax and it’s the British people who are paying the price.”
Mr Ashworth also told Times Radio that the Chancellor Rishi Sunak had taken a conscious decision to "push 1.3 million people into poverty, because he thinks that's a price worth paying."
He said: “The war in Ukraine didn't cut Universal Credit by 20 pounds a week and nor did the global energy markets break the triple lock on the basic state pension, they were ministerial decisions.
"We would be in a better place, if we hadn't had 12 wasted years now.
"The Conservatives are hacking away at the roots of growth. And there were different choices he could have made.”
Earlier Education Secretary Nadhim Zahawi said it would be irresponsible to say “job done” by Mr Sunak over the cost-of-living crisis.
He said: “I think he will continue to keep an eye on this, it’s only right.
“It’s irresponsible for me to say ‘job done’ because energy prices are volatile, inflation remains high, so it would be absolutely irresponsible to say ‘job done’.
“But I think £22 billion, in one year, of help when you’ve just spent £400 billion is the right thing to do.”