A renowned health expert has urged anyone returning to Australia to be stringent about self-isolating for 14 days, calling for tougher measures to ensure the rules are being followed.

Professor Mary Louise McLaws, an adviser to the World Health Organisation and infection control expert, said most COVID-19 cases in Australia had been related to travel.

She told news.com.au the most important thing we should be doing at this stage was frequent checks on recent travellers to ensure they were being diligent about remaining in self-isolation for 14 days.

On Tuesday, the Prime Minister announed Australians would face an imminent ban on travelling overseas.

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According to Australian deputy chief medical officer Paul Kelly, most new diagnoses of coronavirus are related to returning travellers.

But while Australia does have strict penalties for anyone caught breaking the isolation rules – ranging by state from $50,000 fines to up to six months in jail – a consistent process of actually monitoring recent arrivals is where things get tricky.

“We know travellers returning to Australia are the biggest risk,” Prof McLaws said. “Yet at the moment, they are being let out at the airport without being asked how they’re getting home. These are the ones that put the rest of the community at risk.”

The worst example of this, she said, was the Ruby Princess cruise ship that docked in Sydney last Thursday with dozens of undiagnosed coronavirus cases on-board.

Despite several people showing clear flu symptoms, the almost-2700 passengers were allowed to leave the ship at Sydney Harbour, catching trains, buses and even planes to get home. More than 50 people from that ship have since tested positive, making it the largest single source of coronavirus infections in the nation.

“The World Health Organisation says ‘test, test, test’ before isolation,” Prof McLaws said. “That would have been a perfect time to test people before they got off that ship.”

For travellers who do go home, Prof McLaws said “mandatory face-to-face monitoring” was crucial, whether through random home visits, a designated phone or the use of electronic bracelets.

Other countries that have been successful at containing the virus have already implemented tougher measures for travellers.

Last week, Singapore announced it would require all new arrivals to self-isolate for 14 days, warning it would “strictly” enforce the measure.

This rule in itself is not unlike Australia’s and both went into effect around the same time.

But Singapore also has a team of digital detectives whose job is to monitor those under quarantine and trace the travel of confirmed COVID-19 cases.

They then immediately contact anyone else who may have been exposed to the virus and instruct them to self-isolate.

According to the BBC, a British yoga teacher was contacted by Singaporean authorities after she took a six-minute taxi ride where she was potentially exposed to the virus.

The next day, three people turned up at her door, wearing jackets and surgical masks.

“It was a bit like out of a film,” she said. “They gave me a contract – the quarantine order – it says you cannot go outside your home otherwise it’s a fine and jail time. It is a legal document.

“They make it very clear that you cannot leave the house. And I knew I wouldn’t break it. I know that I live in a place where you do what you’re told.”

Inbound travellers to Hong Kong – another area where the virus has been relatively effectively contained – have to wear an electronic bracelet that connects to an app.

Each wristband has a unique QR code. The user then downloads the StayHomeSafe app on their phone and scans the QR code to pair the two.

Once home, the app tracks the user’s whereabouts using geofencing technology and sends an alert to the Department of Health and Hong Kong Police if they stray outside of the zone they’re isolated to – in their words, their own home or residence.

Taiwan – which has been credited as one of the world’s most successful countries in fighting the outbreak – uses similar technology but monitors GPS on phones.

These strict monitoring policies and efficient contact tracing methods, as well as mass testing and social distancing, have been credited as the main reasons these countries have been so successful at helping to contain COVID-19.

If Australia doesn’t do more to ensure travellers are following self-isolation rules, and if the infection rate continues to soar, Prof McLaws warns the rules and restrictions here are likely to become more harsh.