Ministers are racing to prepare the UK for a potential sudden increase in the spread of the coronavirus, with officials fearing it could take just 72 hours for an outbreak the size of Italy’s to take hold.

Amid growing concerns around the world about the pace of the virus’s spread, the health secretary, Matt Hancock, said the government would launch a mass public information campaign giving advice on how to react to suspected cases and guard against infection.

Updating MPs in the House of Commons, he cautioned against overreaction, but acknowledged that the government is expecting more cases in the UK.

The rapid expansion of coronavirus cases in Italy – a key destination for British holidaymakers – has caused concern in recent days and officials are stepping up precautions in case a similar scenario happens in Britain.

The decision to step up preparations in the UK came as the World Health Organization said that the number of new cases being officially reported outside China had overtaken the number within the country for the first time. The WHO chief, Tedros Adhanom Ghebreyesus, described the steep rise in new cases around the world as “deeply concerning”.

There have been 13 cases of the virus so far in the UK, with no deaths. But Italy saw its confirmed cases rocket from just three on Friday to more than 200 by Monday and its total is now 400, with 12 deaths.

On a day of global efforts to limit the spread of Covid-19:

• The total number of infections in Italy represented a rise of 45% in 24 hours. Italian prosecutors opened an investigation into hospital procedures amid claims that an investigation into a so-called “super-spreader” was initially delayed.

• Austria, Croatia and Switzerland reported their first cases linked to the outbreak in Italy. Greece reported its first ever case, which was also linked to the country. France recorded its second death. South America and Norway reported their first cases.

• Event organisers considered their plans as Italy’s rugby match against Ireland in Dublin was called off and questions were raised over the Venice Biennale.

• Around 160 Britons were trapped in a hotel in Tenerife which could stay in lockdown until 10 March.

• 52 further deaths were reported in China, the lowest number in three weeks.

• The WHO warned against using the term “pandemic”, which it said falsely indicated that the spread could no longer be contained.

It is understood that the government’s public information campaign, due to be launched in the coming days, will broadcast advice about calling 111 if coronavirus is suspected.

A Whitehall source said: “It’s as much about winning the battle for public confidence as it is about winning the battle against the disease. There will be social media, stuff on TV, poster campaigns. It will be making sure we can reach as many people as possible.

“It’s making sure that people have got the right advice. At the moment it is very much about telling people to ring 111 … It will be about what people can do to help prevent the spread like handwashing and using tissues.”

The government has been publishing more advice to employers, schools, the travel industry and health workers, but there have been complaints about mixed messages from ministers.

They have said there was no need to shut schools unless a new case is confirmed at the premises, but some 40 schools have either closed their doors or sent pupils home, and the oil giant Chevron ordered 300 traders and other staff at its office in Canary Wharf to work from home. The FTSE 100 has also plummeted on fears of the global economic impact.

As well as increasing concern on UK soil, the government was faced with criticism of alleged inaction and pleas for help from Britons who remain in lockdown at a Tenerife hotel.

Speaking in the Commons, Hancock said that while the government was prepared for a pandemic, it was currently in the “contain” phase and its hope was that all its efforts to contain the virus would prevent that coming to pass.

“The public can be assured that we have a clear plan to contain, delay, research and mitigate, and that we are working methodically through each step to keep the public safe,” he said. “Overreaction has its costs too, economic and social, and so we have to keep the public safe, but we also need to act in a way that’s proportionate.”

Amid concerns about the rights of workers told to self-isolate, the health secretary said the guidance to employers included instructions that such employees were entitled to sick leave.

Q&A How can I protect myself and others from the coronavirus outbreak? Show Hide The World Health Organization is recommending that people take simple precautions to reduce exposure to and transmission of the coronavirus, for which there is no specific cure or vaccine. The UN agency advises people to: Frequently wash their hands with an alcohol-based hand rub or warm water and soap

Cover their mouth and nose with a flexed elbow or tissue when sneezing or coughing

Avoid close contact with anyone who has a fever or cough

Seek early medical help if they have a fever, cough and difficulty breathing, and share their travel history with healthcare providers

Advice about face masks varies. Wearing them while out and about may offer some protection against both spreading and catching the virus via coughs and sneezes, but it is not a cast-iron guarantee of protection Many countries are now enforcing or recommending curfews or lockdowns. Check with your local authorities for up-to-date information about the situation in your area. In the UK, NHS advice is that anyone with symptoms should stay at home for at least 7 days. If you live with other people, they should stay at home for at least 14 days, to avoid spreading the infection outside the home.

“It’s a very important message for employers and for those who can go home and self-isolate as if they were sick because it’s for medical reasons,” he said.

He said that that 7,132 people in the UK had been tested for coronavirus. Of these, 13 had tested positive, eight of whom have since been discharged from hospital.

But Public Health England (PHE) announced that it was stepping up testing to ascertain “whether there’s evidence of infection more widespread than we think there is”. PHE said tests for the virus would be carried out at hospitals as well as at 100 surgeries on people who have “severe respiratory symptoms”.

Prof Jonathan Ball, professor of molecular virology at the University of Nottingham, said the increased surveillance and testing was welcome.

He said: “Many of us have been worried that the virus might be introduced into the UK under the radar and start to transmit more widely in the community. This concern is borne out by the experiences of other countries such as Italy and Iran that are suffering quite large outbreaks where the source of the virus is unknown.”

In parliament, Hancock said the NHS was looking to extend home testing for coronavirus, which has already been piloted in London. “Home testing is the safest place to be tested because then you don’t have to go anywhere, and that will allow us to roll out testing to a much larger number of people as well,” he said.