A government jobs site plagued by fake and fraudulent adverts is "here to stay", according to the head of Jobcentre Plus – but the company contracted to provide the site could still be dumped when its deal expires in 2016.

Internal memos leaked this month suggested the Department for Work and Pensions (DWP) may scrap Universal Jobmatch just 18 months after its launch, following claims it contains hundreds of thousands of false job adverts, some of which result in the risk of identity fraud.

But Jobcentre Plus head Neil Couling released a statement rebutting the claims today, adding that people like and rely on the service.

It read: "Universal Jobmatch is here to stay, which will be of relief to the 500,000 employers and millions of people looking for a new job who rely on it every day.

"Those best placed to judge the system, our users, tell us it they like it and that it makes a real difference to how they look for work."

The statement was co-signed by Sal Iannuzzi, the CEO of recruitment site Monster, which is contracted to provide the site until 2016.

While Couling and Iannuzzi sought to play down reports of a strained relationship between the government and Monster, no guarantee over the provider’s future was given beyond the end of the deal.

The statement simply read: "The DWP – as with any large government procurement – will plan and consider all options for how it delivers the service in the future."

The DWP removed more than 120,000 fake job adverts from 180 so-called employers on the Universal Jobmatch site at the start of March, according to leaked documents seen by the Guardian.

The revelations follow separate investigations by Channel 4 News and Labour MP Frank Field, who claim to have found hundreds of thousands of fake or repeat job listings, some of which aimed to trick jobseekers into spending money on fake criminal record checks.

The DWP told the Guardian that only a fraction of its 524,640 ads do not meet its guidelines, while the latest statement accused critics of misrepresenting the service.

However, it also admitted that the DWP and Monster have had to draw up "new measures" to tackle false listings.

Couling and Iannuzzi added: "Introducing any system, especially in such a complex environment, is challenging. This is why the DWP and Monster are working closely together.

"We listen to feedback, have already made major improvements to the system and are committed to further refinement, if and when necessary."