Benefit claimants struggling to pay their bills will be able to get cash advances upfront, Work and Pensions Secretary David Gauke has said.
He said he recognised concerns that people moving on to Universal Credit had to wait six weeks to be paid.
He told the Conservative conference those needing a cash advance would get one within five days – or on the same day in emergency cases.
But he said he was committed to the system and its rollout would go ahead.
A dozen or so Conservative MPs have called for the rollout of universal credit, which merges six existing benefits into one, to be put on hold because of the financial difficulties facing people arising from the transition from weekly or fortnightly to monthly payments.
Official figures show 24% of new Universal Credit claimants wait longer than six weeks to be paid in full – causing many to fall behind on rent.
The government has insisted the vast majority of claimants were paid in full and on time, and are comfortable managing their money.
Mr Gauke told party conference in Manchester that the shake-up of the benefit system was “working”, giving people more incentives to seek employment and helping people in work secure better-paid jobs.
He insisted that its rollout to more JobCentres across the UK would continue on the present timetable, with the aim of it being fully implemented by 2022.
But he said the rollout would not be “rushed” and he had listened to concerns about how some new claimants were finding it hard to make ends meet.
“I am determined to ensure that those who need support earlier in the month will get it,” he said.
“I can announce today that we are refreshing the guidance to DWP staff to ensure that anyone who needs an advance payment will be offered it up-front.
“Claimants who want an advance payment will not have to wait six weeks. They will receive this advance within five working days. And if someone is in immediate need, then we fast track the payment, meaning they will receive it on the same day.”
He added: “As Conservatives we do not believe, we have never believed, that we can turn our backs on those most in need. As Conservatives we believe in a strong and compassionate welfare state that helps everyone fulfil their potential.”
Speaking earlier on Monday, Chancellor Philip Hammond defended the design of the new system but conceded that some recipients were facing challenges in terms of their cash flow.
Ministers were instructing JobCentre staff to point people proactively to available loan arrangements, he said.