The health secretary says the government is prepared to “do what it takes” to tackle the spread of the coronavirus pandemic.
Emergency legislation that would grant powers aimed at tackling the issue will be debated by MPs later.
Matt Hancock said it was “unfair” that people appeared to be continuing to socialise despite warnings.
Over the weekend, photos emerged showing crowds of people visiting open spaces across many parts of the UK.
Under the proposals to be discussed by MPs, airports could shut and police would be able to force people with virus symptoms to isolate.
According to the latest figures, the UK’s death toll has reached 281 – including a person aged 18 with an underlying health condition. There are now 5,683 confirmed cases.
The government’s emergency legislation – set out last week – includes enabling recently retired NHS staff to return to work without any negative impact on their pensions, fast-tracking funeral arrangements, and allowing more court hearings to take place by phone or video.
Most controversially, the bill gives unprecedented powers to law enforcement agencies to detain people if they show symptoms of the virus and put them in appropriate isolation facilities if necessary.
The powers, which would be time-limited for two years, are expected to be approved by MPs.
The bill says this will help to “safeguard essential services” that could be at risk during the outbreak.
The debate comes after Mr Johnson warned on Sunday that the government would “very actively” consider tougher anti-virus measures over the next 24 hours.
Speaking on Sunday at Downing Street’s daily news conference, Mr Johnson said everyone had to act “responsibly” and practice social distancing.
“If we can’t do that then, yup, I’m afraid we’re going to have to bring forward tougher measures.”
And on Sunday evening, the government issued a further statement, clarifying its advice that “people should avoid travelling unless it is essential”.
Essential travel, the Department for Health and Social Care said, “does not include visits to second homes, camp sites, caravan parks or similar, whether for isolation purposes or holidays”.
The increase of 48 UK virus deaths since Saturday includes 37 in England, seven in Wales, three in Scotland and another in Northern Ireland.
The NHS said all those who died in England in the past day were in vulnerable groups including with underlying health issues.
