The Department for Work and Pensions (DWP) is facing backlash after it emerged thousands of people who care for others are being regularly overpaid and then receiving demands for repayment months or years later.

Calls for the DWP to launch a review into the way it handles Carer’s Allowance are growing louder, as a UK government dementia adviser resigned over the “beyond the pale” prosecutions of carers who had unwittingly gone above the £151 per week earnings threshold.

New figures have revealed that an estimated 34,500 people were overpaid last year, an increase of 4,000 from last year.

While more than 1,000 of those people have been ordered to pay back sums between £5,000 and £20,000, the Guardian is reporting.

Any carer who earns more than the £151 per week limit is expected to pay back their Carer’s Allowance benefit for that week, though many claimants say the rules are unclear.

Johnny Timpson, a government adviser who resigned this week over the matter, told the Guardian: “The fact that we have made absolutely no progress at all on social care [and] we really did not support carers adequately during the pandemic.

“But this latest thing – the approach the DWP are taking to reclaim benefits from carers and people with disabilities, particularly with neurological disabilities – is beyond the pale for me really.”

Ian Duncan Smith, a former Tory work and pensions secretary, has called on the DWP to delay the overpayment claim process.

He told the Guardian: “The best thing is for the DWP now to pause any of these demands, review carefully what was behind all of this to make sure this was not mistakes by DWP but is genuinely about individuals failing to notify the department.”

A DWP spokesman said: “Carers across the UK are unsung heroes who make a huge difference to someone else’s life and we have increased carer’s allowance by almost £1,500 since 2010.

“Our most recent statistics show that carer’s allowance overpayments relating to earnings represents 2.1 per cent of the £3.3bn we spend supporting those who look after loved ones.

“Claimants have a responsibility to inform DWP of any changes in their circumstances that could impact their award, and with safeguards in place to manage repayments, this ensures fairness in our welfare system.”