People should work from home “if they can” to reduce social mixing and slow the spread of the virus, Cabinet Office minister Michael Gove has said.
He also told BBC Breakfast trials of spectators at sports fixtures would be “paused”.
It comes as pubs, bars, restaurants and other hospitality venues in England are told they must have a 22:00 closing time from Thursday.
Full details will be set out by the prime minister in Parliament later.
Boris Johnson will also address the nation in a live broadcast at 20:00 BST on Tuesday.
As well as the early closing time for hospitality venues, he is expected to announce they will be restricted by law to table service only.
On Monday, the UK’s Covid-19 alert level moved to 4, meaning transmission is “high or rising exponentially”.
Mr Gove said that the new advice to work from home where possible was not an “about-turn”, describing it as “a response to the spread of the virus”.
“We’re not going back to the sorts of measures that we had in the spring,” he added.
Mr Gove said plans for sport with live audiences to return from 1 October were being halted “for the moment” because of the risk of fans mixing on the way to the stadium or during half-time.
The government’s chief scientific adviser Sir Patrick Vallance has warned there could be 50,000 new coronavirus cases a day by mid-October without further action – which, he said, could lead to more than 200 deaths per day by mid-November.
Prof Callum Semple, an expert in outbreak medicine at the University of Liverpool, told BBC Breakfast current data was “tracking the worst-case scenario quite accurately”.
He said there was now a rise in hospital admissions, including among women aged 20 to 40, who were at risk of exposure to the virus because of their work in hospitality, caring roles or because they were parents of schoolchildren.
The UK needed “quite a lot more” restrictions in place to prevent the spread, and the hospitality industry will probably have to take another “hit”, Prof Semple said.
Andy Wood, chief executive of the Adnams brewery, told the Today programme that the pub industry had “taken the health messages seriously” and it seemed “incongruous” that it was being singled out.
He said the industry was still “on life support” and about 900,000 jobs were at risk.
On Monday, a further 4,368 daily cases and 11 deaths were reported in the UK. Also:
- Further restrictions will also be announced in Scotland on Tuesday
- Restrictions on households mixing indoors will be extended to all of Northern Ireland
- Also from 18:00 on Tuesday, four more counties in south Wales will face new measures, including a 23:00 curfew for pubs and bars
- New measures will also come into force in Lancashire, Merseyside, parts of the Midlands and West Yorkshire from Tuesday.
- Other areas of England, Scotland and Wales are already under local lockdown, with restrictions including a ban on mixing with other households.
The cabinet meets on Tuesday morning and Boris Johnson will also chair a Cobra emergency meeting – which will be attended by the first ministers of Scotland, Wales and Northern Ireland.
Speaking about the new closing times, a No 10 spokesperson said: “We know this won’t be easy, but we must take further action to control the resurgence in cases of the virus and protect the NHS.”
Tighter restrictions on pub and restaurant opening times are already in place in parts of north-east and north-west England, and Wales.