By Paul Lewis
BBC Radio 4's Money Box
Millions of pensioners and disabled people may face long queues to get their pensions on Christmas Eve.
Millions will have just three and a half hours to get out their money
Many benefits due to be paid on Monday, Tuesday and Wednesday will have to be taken out of Post Offices on Monday morning before they close at 1230.
The Department for Work and Pensions has not brought all payments forward to Friday.
But it says it is confident the Post Office will offer "its usual excellent service".
Who is affected?
Although most people now get their pensions and benefits paid into a bank, about three and a half million only have a Post Office card account or need to cash their payment cheque at the Post Office.
Most pensions are paid on Monday, widow's benefits on Tuesday, and many payments to disabled people on Wednesday.
With Christmas falling on Tuesday the Department for Work and Pensions initially said all those payments could be taken out on Christmas Eve.
But Post Offices close that day at 12.30.
So several million people would have had just three and a half hours to get payments which are normally spread over three days.
WHEN CAN YOU GET YOURS?
Benefits available from Friday 21st December:
Retirement pension (without pension credit), widow's and bereavement benefit, incapacity benefit, and jobseeker's allowance.
Benefits to be collected on Monday 24th December before 12.30pm:
Pension credit (paid with or without state pension), disability living allowance, attendance allowance, carer's allowance and income support.
A late concession by the DWP has brought forward some payments to Friday, including state pensions which do not include any pension credit.
But millions more have not been brought forward.
A spokesman said that computer restrictions had prevented some benefits being advanced to Friday.
And added: "Almost three quarters of pensions will be available on Friday 21 December.
"Pension credit customers will be able to collect their money on Christmas Eve.
"The Post Office has assured us that they will be able to serve all our customers on these days."
But Anna Pearson, policy manager at the charity Help the Aged, says that is not good enough.
"We remain concerned that a Monday payment will leave a lot of the poorest pensioners who get pension credit or disability benefits with very little time to get their weekly food."
BBC Radio 4's Money Box was broadcast on Saturday, 15 December 2007 at 1204 GMT.