Labour's Liam Byrne has outlined the need to "reinvent social security for modern times" as he signalled the party intends to make savings in the welfare budget if it returns to power in 2015.

Pointing to the growing resentment of benefit claimants by some sections of society, the shadow work and pensions secretary said he believed the fact that social security no longer enjoyed "widespread support" was linked to the fact it did not offer the same level of security as it once did.

He said in an era in which "jobs for life" had gone, the system needed to work differently to reflect the fact that different things were needed from social security, with a "much bigger push" to get people back into work, new investment in areas such as childcare, and being "much smarter" about how the system set up to help disabled people worked.

He told the BBC Radio 4 Today programme: "The truth is the world of work has changed very radically since social security was set up back in the 1940s and for many people in work they don't actually feel they get much out for the pressures they have to contend with in everyday life, so I think that fractures support and I think that's why we do have to reinvent social security for modern times and the world today."

Asked whether a Labour government would introduce further welfare savings, Byrne conceded cuts were likely because of the "dog's breakfast" Labour would inherit if it returned to power.

"The national debt is going to be over £400bn higher than it was at the last parliament," he said. "Savings are going to have to be made and I think there will be savings that are needed on welfare spending too, and our challenge is how we spend that money differently to support people in work."

Byrne said the "zero-based review" that Ed Miliband would conduct if Labour won the 2015 general election would look at the "balance" between universal and targeted benefits.

"There has always been a balance in the welfare state between universal benefits and targeted benefits and I'm afraid as part of Ed's zero-based review that balance has got to be looked at, but the chief focus has got to be on getting as many people into jobs as possible. It's good for living standards, it's good for growth and it's good for tax."

Byrne also used the interview to call for a government rethink on its plans to set one national benefits cap, saying it would make "much more sense to have a different cap in different parts of the country".

Speaking before Miliband's party conference speech in Manchester on Tuesday, Byrne suggested an independent panel of experts should examine the issue to ensure "no matter where you live, you are better off in work".

He backed the principle of a cap on benefits, but added: "They have, in a clumsy and pretty politicised way, tried to set one national cap for the country whereas everybody knows that one cap for the whole of Britain would be pumped up a bit by the very, very high levels of rent and housing benefit that you see in London.

"We've said, 'Look, come on, think about this carefully. It would make much more sense to have a different cap in different parts of the country and let's try and take the politics out of that a bit.'

"Let's get an independent panel of wise experts who can look at this and say what is the right level in different parts of the country, so that no matter where you live, you are better off in work."