More than 32,000 people have not received benefit payments in time for Christmas due to a Department for Work and Pensions "administrative error".
The cash was due to go into bank accounts on Christmas Eve but will not now be paid until Friday 27 December.
Most of those affected are first-time claimants or people expecting loans to cover rent and other "essential" items.
The DWP said they would get their money within three hours if they called the department or a Jobcentre by 5pm.
A spokesman said the problem had affected only a "limited number" of claimants, totalling 32,200, and Jobcentre staff were trying to get money to those who got in touch.
"The vast majority of regular benefit payments have been made on time this Christmas," the spokesman added.
"However, due to an administrative issue, a number of one-off or more irregular payments will now be paid on 27 December, rather than the 24th.
"We have procedures in place to ensure that anyone who has been affected by this and who contacts us today (24 December) will get their benefits paid, usually within three hours."
Some of those affected include new claimants waiting for their first payment, those owed arrears, people who have applied for Social Fund budgeting loans, which are a minimum of £100 and are meant to help with the cost of "essential things" such as clothes, rent and furniture.
In "a very few cases" people owed pension-related arrears have also been affected.
The categories of benefits affected include Jobseekers Allowance, Employment Support Allowance, Social Fund and certain categories of pension.
BBC
