A claimant who featured in a Government film about universal-credit said it is riddled with computer problems and could push people into hardship.
In the Department for Work and Pensions (DWP) film, Daniel Pacey said it helped him find work and was far better than jobseeker's allowance.
But he told the BBC a six-week delay before the first payment and further monthly payments were "a nightmare".
The DWP said the benefit replicates the world of work and tackles dependency.
A spokesman said: "Universal credit is simplifying the benefit system and [makes] the transition into employment smoother.
"Our work coaches discuss budgeting support with all claimants and nearly 80% say they are confident in their ability to manage a monthly budget."
Mr Pacey, 24, from Wigan, Greater Manchester, said: ''It might be easy for a government minister to make their wages last a month. But I'd like to see them make £250 last four weeks while looking for work."
He added: ''JSA was just a case of write your name down. Write a couple of jobs down. Hand it in you get paid for it.
"But with this, you really have to work hard to find a job. And it works.''
The government has announced that a national roll-out of universal credit is starting in earnest across the country. The aim is for it to be offered in all job centres in England, Scotland and Wales by 2016.
Work and Pensions Secretary Iain Duncan Smith told BBC News the new benefit was £600m under budget and had been implemented gradually on advice.
But Mr Pacey, who lives with his father, said his job centre struggled with failing computer systems, adding: "I hate to think about how I would have coped had I lived on my own. I know I couldn't have."
The DWP spokesman added: "People can apply for advanced benefit payments if they need extra support and we are working with local authorities to make sure people get budgeting and debt advice.
"The IT system adapts smoothly to claims as they become more complex, which we have already seen across the North West.
"Computer problems in offices are separate issues and are resolved quickly but these do not impact the operating system, or have an impact on claims."
Rent arrears and debt
The scheme was initially piloted in Ashton-Under-Lyne nearly two years ago.
Under the old jobseeker's allowance system, payments were bi-weekly, with housing benefit paid directly to landlords.
Under universal credit, claimants are instead paid monthly and are expected to pay their rent themselves.
Housing Associations in Ashton-Under-Lyne say rent arrears and debt are on the rise amongst universal-credit claimants.
The chief executive of the National Housing Federation David Orr said: "This scheme isn't even ready to fully roll out in Ashton-Under-Lyne, where it's been piloted for two years, let alone the rest of the country."
The DWP spokesman said: "In some cases, we can arrange for alternative payment arrangements, including rent being paid direct to landlords."
The government says it is important for people to learn how to handle their own monthly budgets, as this replicates the world of work.
But Mr Pacey's new job in a call centre pays bi-weekly.
He said: "In my experience, most low-paid jobs pay weekly or every other week, not monthly. You can't make small sums of money last a month.
"It's not about dependency, it's about living, being able to get a bus to go to the job centre. The government needs to rethink this."
Less time and resources
The scheme has also been criticised by the National Audit Office as badly managed and failing to deliver on its targets.
It is concerned that a roll-out from pilot areas in north-west England is taking place with fewer resources to spend on staff training and less time for staff to get accustomed to the changes.
About 50,000 people in selected areas have claimed the benefit since it was introduced in April 2013 - far fewer than the government originally said would be getting it by now.
Computer problems have also caused delays and seen ministers write off tens of millions of pounds.