Labour is to challenge Iain Duncan Smith’s claim that 75% of jobseekers think benefit sanctions have helped them “focus and get on” by lodging a complaint with the official statistics watchdog.

Owen Smith, the shadow work and pensions secretary, said he would write to Duncan Smith challenging him to back up the “groundless” figure and refer the matter to the UK Statistics Authority for investigation.

The work and pensions secretary made the claim in an interview with the Camden New Journal, in which he suggested many claimants were grateful for the consequences of benefit sanctions.

“Seventy-five per cent of all those who have been sanctioned say it helped them focus and get on. Even the people in the jobcentres think it’s the right thing to do ... sanctions are the reason why we now have the highest employment levels ever in the UK, and more women in work,” Duncan Smith said.

“What we say is: ‘We’ll give you all the support but at the end of the day we expect you to do something for it: go back to work, take the job, take the interviews.’ And it works, talk to any of the advisers in the jobcentres.”

While out campaigning for the Tory London mayoral candidate, Zac Goldsmith, Duncan Smith also dismissed protests about the controversial sanctions regime as “a classic buzz from the left” and claimed “these people are never going to vote for us – you have to understand, these people hate us”.

Smith said: “Iain Duncan Smith’s claim that 75% of people who had been sanctioned say it ‘helped them focus and get on’ is groundless and shows he is out of touch with the real impacts of policies introduced by his department.

“In reality, widespread concerns have been raised about this government’s use of sanctions, including from their own advisers, which is why the cross-party work and pensions select committee called for a full independent review into the system.

“However, Iain Duncan Smith is reluctant to accept such scrutiny. Labour is calling for far greater transparency and honesty in this debate, so we can ensure greater numbers of people are actually helped into work, while being treated fairly.

“That is why I will be writing to the secretary of state to inform him that we will refer his use of data to the Statistics Authority and calling for the long overdue independent review into sanctions to begin.”

Duncan Smith is believed to have been referring to DWP research that found 72% of jobseeker’s allowance (JSA) claimants said awareness of sanctions made them “more likely to follow the rules”.

However, that paper also said: “There was no evidence from the survey that knowledge of JSA conditions led to actual movement into work. Respondents who said they were more likely to look for work because of their knowledge of JSA conditions were no more likely than other respondents to have moved into work when they left JSA.”

After the interview, the Department for Work and Pensions released a statement saying: “Decisions on sanctions aren’t taken lightly but are an important part of our benefits system – they are only ever used as a last resort and the number of sanctions continues to fall.”

It is not the first time the UK statistics watchdog has been asked to adjudicate on the DWP’s approach to the sanctions regime.

Last year, it asked the DWP to ensure its statements on jobseeker sanctions are “objective and impartial” following a series of complaints by experts.

At the time, the authority’s chair, Sir Andrew Dilnot, wrote to the DWP’s top statistician asking the department to publish far more data and give the public a clearer understanding of how it is imposing sanctions on jobseekers.

Sanctions are used by civil servants to penalise jobseekers when they are alleged to have broken benefit rules, with punishments becoming increasingly severe over the last parliament.

The government has faced repeated calls from Labour to rethink the system, but is resisting pressure for an independent inquiry.

The Commons work and pensions committee last year urged the government to hold a wide-ranging independent review of the regime to address widespread concerns that it is unfair, excessively punitive, and does little to help people get into work.