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.
Speaking on BBC Breakfast, Mr Hancock said: “We’ve seen with this virus it spreads so easily.
“In other countries in Europe where they didn’t take these crackdowns quite so early, it’s got very serious.
“So of course we’re prepared to do what it takes.”
The health secretary said the government advice on social distancing was “really clear” and people should stay two metres apart and stay at home if at all possible.
“We’ve taken some quite serious actions that have never been seen in peacetime before, like shutting the pubs, bars and restaurants and the police have the power to enforce that now.
“We of course stand ready to take more action if we need to to stop the spread of the virus.”
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.
In other developments, the NHS in England announced it had identified 1.5 million of the most at-risk people who should now stay at home for 12 weeks.
Those at-risk people include those with specific cancers, severe respiratory conditions and people who have received organ transplants.
The government is setting up “hubs” around the country to arrange deliveries of groceries and medicines to them.
Councils, pharmacists and members of the Armed Forces will help this work and there will be opportunities for members of the public to volunteer.
The PM told those people to “shield” themselves, adding it “will do more than any other single measure that we are setting out to save life”.
In other key developments:
- Germany has expanded curbs on social interactions, banning public gatherings of more than two people
- The number of worldwide cases pass 300,000 with more than 13,000 deaths around the world
- Elsewhere in Europe, Spain registered 394 deaths from coronavirus in a day, while Italy recorded another 651
- The International Olympic Committee is considering postponing the Tokyo Olympics in 2020. It has given itself a deadline of four weeks to make a decision
- The Duke and Duchess of Cambridge shared a message of support to families this Mother’s Day, alongside photographs of them with two of their three children, Prince George and Princess Charlotte
- Thousands of retired medics answered the government’s call to return to work to help with the outbreak – including 4,000 nurses and 500 doctors