A record number of almost 1.2 million emergency supplies were given out at food banks in the past year, according to new figures.
The Trussell Trust said its network provided 1,182,954 three-day food supplies to people "in crisis" in the year to March - over 70,000 more than the previous 12 months.
The charity said almost 440,000 supplies went to children.
Food banks in areas where the new Universal Credit (UC) benefit was introduced saw an average increase in referrals for emergency food of almost 17%.
The trust said the effect of a six-week waiting period for a first UC payment could be serious, leading to debt and rent arrears.
Benefit delays and changes remain the biggest cause of someone being referred to a food bank by a doctor, social worker or jobcentre.
David McAuley, chief executive of the Trussell Trust, said: "The move to simplify an often complex welfare system is a welcome one, but any large reform can have unforeseen consequences.
"Food banks see first-hand how changes to the welfare system affect people on the ground and so can offer an early warning to decision-makers.
"We are sharing our early observations with the Department for Work and Pensions to ensure any adverse side-effects Universal Credit can have on people are addressed before full rollout is completed.
"We have been heartened by Secretary of State Damian Green's willingness to engage, his department's work to pilot improvements, and the recent changes to the Universal Credit taper rate which mean people moving into work will keep more of their earnings.
"We hope our insights can inform efforts to make sure the values on which Universal Credit is built are delivered in practice. To stop UK hunger, we must make sure the welfare system really does work for everyone."
The Trussell Trust has more than 420 food banks around the country, with people having an average of two referrals in the past year.
In the North East, it has food banks in Hartlepool, Billingham, Stockton Redcar, Gateshead, Newcastle and throughout County Durham.
A Department for Work and Pensions spokesman said: "The reasons for food bank use are complex, so it's misleading to link them to any one issue.
"Under Universal Credit people are moving into work faster and staying in work longer than under the old system.
"Universal Credit is designed to mirror the world of work and give people control over their own finances.
"The majority of UC claimants are confident in managing their money and we work closely with local authorities to support those who need extra help. Budgeting support, benefit advances, and direct rent payments to landlords are available to those who need them."