Labour will "pause" the government's flagship welfare reform if it wins the next general election in 2015, shadow work and pensions secretary Rachel Reeves has said.{jcomments on}
Ms Reeves said her party supported the universal credit policy in principle, and hoped to "rescue" it.
She said the Department for Work and Pensions had been in "chaos" under her opposite number, Iain Duncan Smith.
Mr Duncan Smith said implementation of the project was now "working well".
The universal credit system merges six working-age benefits - income-based jobseeker's allowance, income-related employment and support allowance, income support, child tax credit, working tax credit and housing benefit - into a single payment in a far-reaching change designed to encourage work and reduce fraud.
In an interview with BBC One's Sunday Politics programme, Ms Reeves said: "We set up a universal credit rescue committee in the autumn of last year because we had seen, from the National Audit Office [and] from the Public Accounts Committee, report after report showing that this project is massively over budget, and it is not going to be delivered according to the government timetable.
Mr Duncan Smith told Pienaar's Politics: "Once you've got it set in the North West you can then roll it out all over the rest of the country knowing that you are likely to achieve what you set out to do."
He said reports that the policy might be abandoned were "complete nonsense", adding: "All our IT at the moment is working and it's working well, which is why we've taken the decision to roll it out to the whole of the North West."
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