HMRC has admitted running over budget on its Real Time Information (RTI) development, the PAYE system crucial to the roll-out of Universal Credit next year.
Some £124m had originally been earmarked for the project in 2010, said David Gauke, exchequer secretary to the Treasury in a Parliamentary response.
But following public consultation, changes in the design of RTI have been made, resulting in additional costs.
Plans for the pilot year have also changed, Gauke responded to a question from Stephen Timms, Labour MP for East Ham.
Timms told Computer Weekly the response contradicted HMRC’s assertion the programme was running to schedule.
"Until very recently, HMRC insisted this project was on budget. Now they say they don't know how much it will cost," said Timms.
"HMRC also recently announced that penalties for late RTI submissions will not be collected from employers in the first year of RTI. That sounds like recognition the system won't work properly until a year late.”
Gauke said: “HMRC are working to determine the scale of the increase and are looking at how these additional costs will be met.”
The IT behind Universal Credit (UC) has hit major problems, with the £2.2bn project running significantly over budget. The senior leadership team underwent a major overhaul as Philip Langsdale stepped up to oversee the UC overhaul, with programme director Malcolm Whitehouse among a number of senior figures to step down.