The government has urged Whitehall bosses to “move quickly” to return to office with more staff fees.
In a letter seen by the BBC, he says he “strongly encourages” attendance by Rota Systems, arguing that this would be “greatly beneficial”.
It follows criticism that many fewer civil servants working from home have returned to their desks despite the ease of lockdown due to the coronavirus.
But unions have called the government’s stance outdated.
They say most civil servants should expect to continue working from home by the end of the year and are at risk of catching coronavirus when they return with colleagues.
An analysis of mobile phone data last month indicated that only 17% of UK workers have returned to office fees.
The government has launched a campaign to encourage people in the workplace after business leaders, including the head of British industry (CBI), warned that city centers could become “haunted towns”.
CBI’s Dame Caroline Fairben said thousands of businesses that rely on passing trade are suffering while offices are empty.
But Alex Brazier, executive director of Bank of England for Financial Stability, warns that the government should not expect “sharp returns” for the “ga office fee environment”.
The government says it wants 80% of civil servants to be able to attend their normal workplace once a week by the end of September.
And Prime Minister Boris Johnson has asked officials for a weekly update on progress.
“More people will be brought back to work in a covid-safe way. Improve the public services we deliver,” said Cabinet Secretary Sir Mark Sedville and Chief Operating Officer of the Civil Service Alex Chisholm in a letter to permanent secretaries – top officials – in government departments.
He adds: “We have seen low levels of social interaction among our colleagues, including the lack of some spontaneous interaction and cross-fertilization between teams running for sustainability and general purpose.”
But he says staff safety remains “our best concern”, and that workplace compensation will be discussed with unions and staff groups.
The letter goes on to say: “Departments that are still below their departmental barriers should now move quickly to try to bring more staff back to the fees in a covid-safe manner, and take advantage of the return to schools this month and increased public transport availability.”
The FDA union, which represents senior civil servants, said this week that it expects 30% to 40% to return to office by the end of the year.
Leader Dave Penman accused ministers of “raising their voices like ludites” in an age when techno-home makes homework easier.
And Mark Servotka, general secretary of the Union of Public and Commercial Services, said he was prepared to consider industrial action “as a last resort” if workers’ health and safety were “put at risk”.
Meanwhile, Capita, a major government contractor – outsourcing company – is planning to close more than a third of its offices in the UK permanently.