Health Secretary Matt Hancock has said he has “absolutely no idea” how many people in his department are currently working from home.
It came after CBI director-general Carolyn Fairbairn urged the Government to lead firms in getting staff back to the workplace.
Ms Fairbairn warned that commercial centres risk becoming permanent “ghost towns” and said that returning employees to offices is as important as getting pupils back to schools.
In an interview on Times Radio, Mr Hancock was asked if he knew what percentage of staff in the Department for Health were working at home.
“I have absolutely no idea,” he responded.
“What I care about is how effectively people work and obviously people should come back to the office if that is what they need to do their job.
“And also employers need to make sure the offices are Covid-secure, as we have obviously in the Department for Health, as you would fully expect us to.
“But what I care about is that people perform and so the people I work with, some of them have been working from home, some come in sometimes, some are in full-time, and what matters to me is that they deliver and, frankly, they’ve been delivering at an unbelievable rate.
“I mean, you know, there’s sometimes this caricature that people who work in the Civil Service work a 9 to 5 day, it’s just completely untrue in my experience.
“And people are working incredibly hard because, ultimately, it’s a mission-driven job and, in the middle of a pandemic, the whole department has stepped up to that mission.”
The Health Secretary also said that getting staff back to work is a matter for employers.
Mr Hancock said: “I think that this has got to be done across the board. If you think about the nation as a whole, it’s got to be done in a Covid-secure way.
“But employers are doing that and the rules are clear about that.”
He added: “I see that the CBI yesterday put out a statement saying that people need to get back to the office, and I’ve been talking to the chief of the CBI about what more we can do in addition to saying that the rules are that this is a matter for employers so long as their place of employment is Covid-secure.
“And of course we’ll work with the CBI on the things that they want to see to help make this happen.”
Meanwhile, a poll published in the Telegraph newspaper suggests that a third of British workers expect to work from home after the pandemic.
A University College London study found that 32% of 30 to 59-year-olds and 29% of 18 to 29-year-olds said they plan to work from home more after the pandemic ends.