The Liberal Democrats will pledge in their general election manifesto to introduce a new "yellow card" system to give job seekers who break benefit rules a final warning before sanctions are imposed.
Amid Lib Dem concerns at a dramatic increase in sanctions in recent years, the party will say that benefit recipients should be given "fair warning" before they forfeit their benefits.
In another sign of their determination to differentiate themselves from their Tory coalition partners, the Lib Dems will say the system needs to be reformed after a trebling in sanctions.
Under the current rules, claimants can lose four weeks of benefit for something as simple as missing one appointment at a JobCentre Plus office.
The Lib Dems say that over the past decade the number of sanction referrals has increased from around 60,000 a month in the early part of the last decade to around 170,000 today. Sanctions can be imposed if job seekers fail to meet simple conditions such as writing a CV, applying for enough jobs or turning up to interviews.
The party points to figures which show that in 2013 around 6,700 sanctions were overturned each month – 15% of the total – on the grounds that the original decision was flawed. In many cases the claimant provided extra information which helped to overturn the sanctions.
Steve Webb, the Lib Dem work and pensions minister, said: "The Liberal Democrats believe in offering opportunity for everyone in order to build a stronger economy and a fairer society. That's why we are reforming the benefits system to make sure that work always pays.
"It's absolutely right that when we pay people benefits that there are expectations of them and consequences if they don't meet those expectations. But the process needs to be fair and clear.
"There are too many examples of cases where people have been penalised unfairly. The Liberal Democrats want to build a fairer society and that's why we think that before people's money is taken away, they should get fair warning."
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