People in England should work from home "if they can" to reduce social mixing and slow the spread of the virus, Michael Gove has said.
And plans to have spectators at sports fixtures would "pause", the Cabinet Office Minister told BBC Breakfast.
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 met the first ministers of Scotland, Wales and Northern Ireland and will 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.
In July, the prime minister said people should "start to go back to work now if you can" and last month the government launched a campaign to encourage workers back to offices.
Mr Gove told BBC Radio 4's Today programme: "We are stressing that if it is safe to work in your workplace, if you are in a Covid-secure workplace, then you should be there if your job requires it.
"But, if you can work from home you should."
Asked if that was a change in advice, Mr Gove said: "Yes."
The new message brings England into line with Scotland, Wales and Northern Ireland, which have all advised people to work from home wherever possible throughout the pandemic.
But Mr Gove told BBC Breakfast the country was "not going back to the sorts of measures that we had in the spring" when strict measures were imposed.
Plans for sport with live audiences to return from 1 October in England were also being halted "for the moment" because of the risk of fans mixing on the way to the stadium or during half-time, Mr Gove added.
Labour leader Sir Keir Starmer said a second national lockdown would be "a sign of government failure, not an act of God".
"It would take an immense toll on people's physical and mental health and on the economy. We need a national effort to prevent a national lockdown," he told the Labour Party conference, which is taking place virtually.
'Government says the risk has changed'
Remember all that stuff a few weeks back about going back to the office?
Well, don't. Or at least don't unless you need to.
The government says it is changing tack on its guidance for England because the risk has changed - and that is why it wants pubs to shut early too.
There's been passionate discussion among ministers about how far to go with these measures - some wanting the prime minister to go further, faster - others urging restraint.
It illustrates the central dilemma here: Calibrating a sufficient response to a still dangerous virus, while protecting liberties and minimising economic havoc.
On Monday, the UK's Covid-19 alert level moved to 4, meaning transmission is "high or rising exponentially".
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.
Deaths remain low at the moment, however, with the Office of National Statistics reporting that coronavirus accounted for only 1% of deaths in England and Wales in the week to 11 September.
But this week also marks the first time deaths have increased rather than fallen since the beginning of April, and there are fears that rising numbers of patients in hospital will lead to more fatalities.
'A disconnect between scientists and ministers'
First it was the scientists, now it's the turn of ministers.
On Monday the government's two most senior coronavirus advisers - Prof Chris Whitty and Sir Patrick Vallance - set out the scale of the problem. Today ministers are coming forward with the solution.
The scientists' warning was dire - the UK could see 50,000 cases by mid October - up from under 4,000 a day on average currently.
The government response? So far what we've heard on government policy for England is that pubs will have to close early and that you should work from home if you can (although more restrictions may be announced later).
There seems to be a disconnect between the two groups. Why?
Some experts have described the 50,000 figures as implausible. France and Spain - who are a few weeks ahead of us - are nowhere near that trajectory. What is more, the rule-of-six brought in last week has not had a chance to have an impact.
Many believe what we are seeing now is a natural drift upwards - society has re-opened and it is the time of year when respiratory viruses circulate more.
So why all the doom and gloom? There are three ways of looking at it. Firstly, that we are truly on the brink of an explosion in cases (they, after all, are the experts and have access to all the data).
Secondly, that they are worried (some argue unnecessarily given hospital cases remain low) and are softening the public up for more restrictions. The other is that they are trying to influence behaviour so more draconian restrictions are not needed.
Just how far the prime minister goes this afternoon will be telling.
Prof Calum 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.
But the industry has warned the new rules will be "absolutely devastating" for pubs and restaurants, leaving some businesses unable to cover their costs.
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.
New measures against the spread of the virus are being implemented across the nations and regions of the UK:
- Further restrictions will also be announced in Scotland on Tuesday
- Restrictions on households mixing indoors will be extended to all of Northern Ireland from 18:00
- Also from 18:00, 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
- Other areas of England, Scotland and Wales are already under local lockdown, with restrictions including a ban on mixing with other households.
The cabinet met on Tuesday morning and Boris Johnson also chaired a Cobra emergency meeting - 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.
On Monday, a further 4,368 daily cases and 11 deaths were reported in the UK.