A spokesman said the UK government had a responsibility to “use every means possible” to keep the public informed during the pandemic.
He said: “Our use of social media influencers has meant over 7 million people have been reached. This is just one part of a wider campaign utilising TV, radio, social, print and other advertisements to ensure the public has the information it needs.”
It comes as the Sunday Mirror reported Love Island stars Shaughna Phillips, Chris Hughes and Josh Denzel were among those paid by the Cabinet Office to tell their online followers testing for Covid-19 was “free, quick and vital to stop the spread”.
But Phillips and Hughes have also both posted images online in the last month which showed them failing to socially distance from others on Mediterranean islands.
The Mirror cited a social media expert as saying the stars would usually command between £5,000 and £10,000 (€5,500-€11,000) for an ad post.
The UK government’s spokesman said: “All costs involved in the campaign will be published as part of the regular transparency reports on gov.uk.”
The celebrities could also face an investigation by the UK Advertising Standards Agency after not initially labelling their posts as advertisements.
The spokesman indicated the UK Cabinet Office had been clear about labelling such content correctly and noted all three posts had “now” been marked as ads.
It comes after recent data showed three-quarters of close contacts of people who tested positive for Covid-19 were reached through the test and trace system, once again falling short of Britain’s target.
Some 75.5 per cent of close contacts in England were reached in the week ending August 19.
While this is up from 71.6 per cent in the previous week, it is the ninth week in a row where the British government’s Scientific Advisory Group for Emergencies (Sage) target of isolating 80 per cent of contacts of coronavirus cases within 48-72 hours has been missed.
Ahead of the figures being published, England's Health Secretary Matt Hancock acknowledged the system was “not quite there”.
