The chancellor has reiterated slotxo the £20 uplift to universal credit will be scrapped as it "was always intended to be a temporary measure".
Campaigners say the payments, worth around £1,000 a year, have stopped some from falling into poverty.
Labour's leader Sir Keir Starmer said taking the payments away was "simply wrong in principle".
The decision has also been criticised by prominent Conservatives.
Universal credit is claimed by more than 5.5 million households in the UK.
It was introduced to replace six benefits and merge them into one benefit payment for working-age people.
The £20 top up was extended by six months in March and Labour has called for it to continue beyond the autumn.
Speaking on BBC Breakfast, Mr Sunak said the uplift was part of "things we put in place to deal with the crisis" of the pandemic, adding "those things will come to an end, much like the furlough scheme".
He said the uplift had only been "one part of our overall package of support" for people, adding that the government's plan of getting people back into work "is working".
"Those on the lowest incomes have seen the most support from the government, but going forward, my view and the government's point of view is the best way to help people is to help them into work and make sure those jobs are well paid", he said.
But former Conservative work and pensions secretary, Iain Duncan-Smith, said the "government needs to think again".
"This uplift simply restores what was in initially intended for universal credit", he said.