The Prime Minister said people should “try to lead their lives more normally” as restrictions are eased after months of lockdown.
And he hinted that stricter rules on wearing face coverings in public places may be introduced in a bid to reduce the spread of coronavirus.
In an online question and answer session with the public, Mr Johnson said: “I want people to go back to work as carefully as possible. It’s very important that people should be going back to work if they can now.
“I think everybody has sort of taken the ‘stay at home if you can’ – I think we should now say, well, ‘go back to work if you can’. Because I think it’s very important that people should try to lead their lives more normally.
“I want to see more people feeling confident to use the shops, use the restaurants, and get back into work – but only if we all follow the guidance.”
He later added that people should only return if their company is obeying the guidelines and it is safe to do so.
The PM said that as the number of coronavirus cases falls, the rules on wearing face coverings need to be “stricter”.
“I do think we need to be stricter in insisting people wear face coverings in confined spaces where they are meeting people they don’t normally meet,” he said.
“We are looking at ways of making sure that people really do have face coverings in shops, for instance, where there is a risk of transmission.”
Face coverings are currently compulsory on public transport and in hospitals in England, but are only advised in other enclosed public spaces where social distancing is not possible and where “you will come into contact with people you do not normally meet”.
In Scotland, people are legally obliged to wear face coverings inside shops and on public transport.
It is understood that the issue is being looked at inside Number 10.
Earlier this week, the World Health Organisation acknowledged there is “emerging evidence” that Covid-19 could be spread through particles in the air.
And the president of the Royal Society, Professor Venki Ramakrishnan, said everyone should wear a face covering in public to reduce the risk of a second wave of Covid-19 infection.
Mr Johnson also said he wanted to see universities return along with schools this autumn.
“I want that to happen, it should happen, it must happen,” he told the ‘People’s PMQs’ question session.
The PM also said it was important to suppress coronavirus ahead of the winter when the disease could come back.
“If we do that we have got a fantastic chance of slowly getting the economy going again over the summer, keeping it down, and then being in a good position for the colder months,” he said during the online question and answer session.
“It is going to be the winter where we are really going to have to be on it, because that is when you are going to get flu, you are going to get real problems of general public health, and there is a risk that the virus will come back again anyway.
“It is so important now to make real, real progress in driving it down.”