Ms Rudd said it was “absolutely clear” there had been issues with the roll-out and said people being unable to access money “led to an increase in food bank use”.
Labour MP Sharon Hodgson (Washington and Sunderland West) had asked about the impact of the roll-out during Department for Work and Pensions (DWP) questions in the Commons.
The DWP Secretary said: “We’re committed to a strong safety net where people need it.
“It’s absolutely clear there were challenges with the initial roll-out of universal credit and the main issue that led to an increase in food bank use could have been the fact that people had difficulties accessing their money early enough.
“We have made changes to accessing universal credit so people can have advances, so there is a legacy run on after two weeks of housing benefit, and we believe that will help with food bank use.”
“That’s why we have listened and made improvements, such as extending advances, removing waiting days and introducing Housing Benefit run-on.
“These changes are giving support to vulnerable people who need it most, while at the same time helping people get into work faster.”
Mrs Hodgson, who is co-chairing the Children’s Future Food inquiry, told the Commons her investigations into families struggling to feed their children showed the roll-out had left them “worse not better” off.
She said: “It is complex but they’re telling me universal credit is making their situation worse not better.
“Will she join me in April at the launch of this report and will she tackle children’s food insecurity as a matter of urgency?”
Ms Rudd responded positively, saying: “I am as committed, as she is, about tackling food insecurity, obviously particularly for children.
Downing Street did not distance itself from her admission, with Prime Minister Theresa May’s official spokesman saying the Government had “long acknowledged” problems with the initial introduction of UC.
Shadow work and pensions secretary Margaret Greenwood said that the initial wait for a UC payment after first claiming the benefit was “pushing many families into poverty”.
“It is no wonder that many people are being driven towards food banks,” she said. “It is astonishing that the Amber Rudd has admitted this link yet she has failed to take action on the five-week wait.
“I believe and hope the changes we have made about accessing early funds will have reduced food insecurity but of course I will take an early interest in the report she is producing and I look forward to seeing it.”
Liberal Democrat work and pensions spokeswoman Christine Jardine said: “This belated admission of responsibility comes far too late for the tens of thousands of people forced to rely on food banks because of the Conservatives’ stubborn refusal to fix Universal Credit.
“In 21st century Britain, no-one should be dependent on charitable handouts for their survival, yet that is precisely the situation that Government policy has created.”
SNP MSP George Adam said Ms Rudd’s admission was “long overdue”.