There are no plans to make face coverings mandatory for office workers in England, Matt Hancock has said.
The health secretary told BBC Breakfast people working in offices will not need to cover up, despite a newspaper report suggesting they would have to.
“It is something we’ve looked at and rejected,” he said, but added masks would be worn elsewhere by the public “for the foreseeable future”.
Face coverings in shops will become mandatory in England on 24 July.
Mr Hancock said coverings help prevent spread during brief encounters with strangers, but that social distancing and hand washing are more effective for contact with people over long periods of time.
There is a difference between visiting a shop for a few minutes and working alongside colleagues at a desk for several hours, he said.
“When you’re in close proximity with somebody that you have to work closely to, if you’re there for a long time with them, then a mask doesn’t offer that protection.
“The same logic applies for schools – we’re not recommending masks for schools because if you’re in a classroom with kids all day then a mask doesn’t give you protection.”
Mr Hancock said face coverings were effective “in a shop or public transport, for instance, when you’re with somebody for a reasonable amount of time – a few minutes – but not all day.”
“The point is when you’re in interaction with people who you aren’t normally with, that’s where the mask may be particularly helpful.”
He added: “We are not proposing to extend masks to offices.”
Mr Hancock said the public needed to get used to wearing face coverings in shops and at NHS facilities “for the foreseeable future”.
“People have got to play their part,” he said.
It comes after it was announced those who fail to comply with the new rules on wearing face coverings in England’s shops will face a fine of up to £100.
Children under 11, those with certain disabilities, and people working in shops will be exempt.
Scotland already requires shoppers to cover their faces while Wales and Northern Ireland are both weighing similar policies.
Mr Hancock told the Commons on Tuesday the new rule would “give people more confidence to shop safely and enhance protections for those who work in shops”.
Mask-wearing has been compulsory on public transport in England and at NHS facilities across the UK since 15 June.