The government's controversial Work Programme helped 62,000 people into employment between April and June 2013, according to research by the Employment Related Services Association (ERSA).

The trade body, which represents organisations delivering employment related services, revealed that the new total number of people helped into work is 384,000, up from 321,000 at the end of March 2013.

The data, which was collected from all 18 prime contractors of the scheme, found that more than 100,000 18 to 24 year olds have found some employment through the initiative.

But the figures also demonstrated that only 39% of those who have been on the programme for the full two years have so far entered work.

Kirsty McHugh, chief executive of ERSA, said: "Over the last two years, performance on the Work Programme has continued to build.

"Our evidence indicates that more than 70% of these will go into sustained employment, transforming their lives and saving millions of pounds for the taxpayer."

But Jenny Gulliford, a research and policy assistant at the Work Foundation, was cautious about the figures.

"Whilst ERSA's statistics are useful (and provide some interesting information on job start/job outcome conversion rates), they are not as reliable as government figures," she warned.

"But as long as you take ERSA's statistics at face value - as figures being produced by a trade body - they are useful."

Dave Simmonds, chief executive of think tank the Centre for Economic and Social Inclusion, said the data showed a steady increase in performance, but described the government's annually set achievement measurements for Work Programme providers, minimum performance levels (MPLs), as "flawed".

MPLs have also been criticised by Work Programme contractor G4S. The outsourcer called on the government to scrap the measure.

"The government should replace MPLs with a cohort based measure capturing the number of jobseekers who have achieved sustained employment during a given period of time," said G4S.

"The unrealistic nature of MPLs has undermined the credibility of the programme and negatively impacted on provider investment due to inflated risk and lower returns."

The news follows criticism from a cross-party group of politicians in May 2013 which claimed the scheme fails its most vulnerable participants.

Parliament's Work and Pensions Committee (WPC) said that the hardest cases - such as those with disabilities or a history of substance abuse - are being "parked" by those providing the Work Programme, who cannot cope with the problems they are faced with.

Instead, the providers are "creaming" the simplest cases off, in pursuit of an easy payment from the government.

"It is clear that the differential pricing structure is not a panacea for tackling creaming and parking," said Dame Anne Begg MP, WPC chairwoman.

Mark Hoban, Minister for Employment, added: "The Work Programme is designed to give two years of tailored support to some of the hardest to help jobseekers, with providers only paid when they deliver results, so it's good news that hundreds of thousands of people have been helped into work.

"Following the good employment figures this week which showed a record number of people in work, this is a further sign that we are able to compete in the global race."

The government's official statistics on sustained job outcomes and sustainments will be published on 26 September 2013.