A health official in the US has the Internet talking after warning people not to touch their face at risk of spreading coronavirus, then immediately ignoring her own advice.

Dr Sara Cody from the Santa Clara County Public Health Department in California was unable to avoid her own bad habit of licking her finger to turn a page while warning people in her area how to avoid catching Covid-19.

The ill-timed incident happened mid-way through a press conference in Santa Clara County, California, right after the public health officer gave this advice:

"Start working on not touching your face, because one main way viruses spread is when you touch your own mouth, nose or eyes."

Much like the global health crisis she's discussing, video of the incident has gone viral, notching up more than 6.6 million views since it was posted on Twitter this week.

Disgusted, amused and understanding viewers were quick to chime in on the finger-licking saga, sharing their own words of advice and cautionary tales.

"Licking his finger while counting money is how my manager at Blockbuster got meningitis and then died. DON'T LICK THINGS, PEOPLE," implored a Twitter user.

"This is funny and shows how incredibly hard it is to do," said another.

"We all touch our face all the time subconsciously. She has no idea what she just did. It's difficult to break these habits without a concerted effort," agreed a third.

Proving just how blithely unaware we are to these types of self behaviours was US congress member Alexandria Ocasio-Cortez, who repeatedly touched her face while speaking to the press about coronavirus this week.

Similarly, Twitter users have called out President Trump who recently claimed that he hadn't touched his face "in weeks," despite being photographed doing otherwise.

The World Health Organisation has urged governments around the world to pull out "all the stops" to slow the spread of the coronavirus.

To date, the virus has infected nearly 97,000 people and killed more than 3,300.

New developments in the spread of coronavirus emerged around Australia overnight: a NSW high school has been closed today to due to a confirmed case of the new COVID-19 virus strain, WA confirmed its third case in a woman returning from the UK on an Emirates flight, and supermarkets are introducing new restrictions to combat panic-buying.

Four Australians on a cruise ship off the coast of California are waiting to find out their next destination, after at least 15 on-board tested positive to the disease.