No 10 says a review into the 2m social distancing rule will be completed “in the coming weeks”.
However the PM’s spokesman could not say if it would be done by the time hospitality venues in England are due to reopen on 4 July.
The government has come under pressure from the hospitality industry and its own MPs to relax the 2m rule.
The spokesman said the government was in talks with hospitality but there was a duty to ensure reopening was “safe”.
The announcement comes as some shops in England reopen for the first time since the lockdown was introduced, with long queues reported outside Primark shops in London and Birmingham.
Retailers will still have to enforce strict safety measures including implementing one-way systems and abiding by the 2m social distancing rule.
Under the rule, the UK government currently advises people to stay 2m (6ft 6in) apart from others to avoid spreading coronavirus.
This is further than the World Health Organization’s recommendation of at least 1m (just over 3ft), and some other countries like France and Denmark. But the government’s scientific advisers say that being 1m apart carries up to 10 times the risk of being 2m apart.
Some bars, restaurants and pubs say they will be unable to make a profit if the 2m guidance is still in place when they reopen. Tourism firms have also warned of tens of thousands of job losses unless the distance is shortened.
Kate Nicholls, chief executive of the industry body UK Hospitality, says that with a 2m rule, outlets would be only able to make about 30% of normal revenues, whereas 1m would increase that to 60-75%.
Speaking to BBC Breakfast, she said: “We very much welcome the government’s decision to conduct a review on this because it is a matter of survival or business failure as far as hospitality is concerned.”
Relaxing the 2m rule could also allow more children to return to school. Hamid Patel, chief executive of the Star Academy Group, has said that with 2m distancing in place, no more than 50% of secondary pupils could attend, and in some schools it would be lower.
‘Margin for manoeuvre’
On Sunday, the government announced it would be reviewing the rule, with Prime Minister Boris Johnson saying there would be “margin for manoeuvre” as the number of coronavirus cases falls.
Mr Johnson said: “As we get the numbers down, so it becomes one in 1,000, one in 1,600, maybe even fewer, your chances of being two metres, or one metre, or even a foot away from somebody who has the virus is obviously going down statistically.”
The PM’s spokesman said the review would look at transmission of coronavirus in different environments, incidence rates and international comparisons.
It is to be chaired by Simon Case, the No 10 permanent secretary and will take evidence from medical experts, economists as well as considering papers from SAGE (Scientific Advisory Group for Emergencies).
Speaking to the BBC, Business Minister Paul Scully said the Government did not want to be “rushed into decisions as we gradually open up the economy”.
Shadow justice secretary David Lammy said Labour would support a relaxation of the 2m rule if the evidence showed it was “the right time to do it”.
Speaking on the Andrew Marr programme on Sunday, he said the government should “follow the science,” and be “frank and honest with the public on balancing risk”.
He added: “I think the government’s been slow, slow on testing, slow on lockdown, slow on PPE [personal protective equipment], and I suspect they’ll be slow again on this”.
‘Safest place to be’
The 2m distance has been implemented by all nations of the UK, which have their own powers over restrictions. But so far, political leaders have rejected calls to relax the 2m rule.
First Minister Nicola Sturgeon said she was looking at “ongoing evidence” but added that she would not be setting a timescale for easing the rule.
“It’s really important that it, or any other single aspect of trying to suppress this virus is not looked at in isolation,” she said.
“If you reduce the distance that are other things you have to consider about like face coverings – and also the, the amount of time it is then safe for people to be in that kind of proximity.”
And Northern Ireland’s First Minister Arlene Foster said the medical advice suggested 2m apart was the “safest place to be”.
While pubs, bars and restaurants could open in England from 4 July, no date has been given in Scotland, Wales or NI.
In Northern Ireland, all shops were allowed to open from Friday. No dates have been set for the reopening of non-essential shops in Scotland and Wales, although each country has set out its planned stages for lifting lockdown.
The UK government has repeatedly said it is constantly reviewing its coronavirus lockdown guidance.