There should be an “urgent review” of 10pm closure times for restaurants and pubs, Greater Manchester’s mayor says.
Andy Burnham said it meant people were gathering in homes and supermarkets that were “packed out to the rafters” once the bars closed.
Scenes of crowds forming after closing time have been filmed in UK cities including Liverpool and York.
There are no specific plans to review the policy, but all measures are kept under review, the PM’s spokesman said.
He highlighted a police statement that said the crowds seen in Liverpool over the weekend were dispersed within minutes, with the city centre “virtually empty” by 22:30.
The 22:00 closing time had been used in local lockdown areas and experience there suggested it struck “the right balance”, allowing businesses to trade “for the majority of the evening”, the spokesman added.
Under the new restrictions, all pubs, bars and restaurants in England and Scotland are to provide table service only and must shut no later than 22:00.
Mr Burnham said people gathering after closures was “the opposite of what local restrictions here are trying to do”.
“My gut feeling is that this curfew is doing more harm than good,” he told BBC Radio 4’s Today programme.
“I think there needs to be an urgent review of the emerging evidence from police forces across the country.”
He suggested one option could be to impose a 21:00 cut-off on alcohol sales in shops to prevent the rush to off-licences after the pubs close.
Mr Burnham has also called for more financial support for areas under greater restrictions and tougher powers for local areas to close businesses not observing the rules.
Senior Conservative MP Tobias Ellwood said the 22:00 closing time “makes no sense”, saying figures suggested only 5% of coronavirus outbreaks were linked to hospitality.
John Apter, national chairman of the Police Federation, said: “My colleagues will do the best they can to encourage and coerce people to move on but it is really difficult.
“All that you need is a hostile group that turns against those officers and the resources for that city centre are swallowed up dealing with that one incident.”
Health minister Helen Whately defended the policy and urged people to head home after their evenings out.
She said the government was keeping an “open mind” about the new regulations.