FRENCH health authorities say they fear the country's first case of a new SARS-like virus that has killed 18 people, mostly in Saudi Arabia, may have infected two other people.

The 65-year-old man who came back to France from a holiday in Dubai was diagnosed with the deadly novel coronavirus, and is in intensive care in a hospital in the northern city of Douai, the health ministry said Wednesday.

"This is the first and only confirmed case in France to date," it added.

But on Thursday the health authorities in the Nord/Pas-de-Calais region said two more people were undergoing tests after showing symptoms of the virus.

They were a man who had shared a room in hospital with the patient, and a doctor who treated him.

The unnamed patient, who was in Dubai from April 9 to 17, has been placed in isolation and is being given respiratory assistance and blood transfusions.

The virus, known as nCoV-EMC, is a cousin of Severe Acute Respiratory Syndrome (SARS), which triggered a scare 10 years ago when it erupted in east Asia, leaping to humans from animal hosts and killing some 800 people.

It was first detected in September 2012 and since then more than 30 cases have been reported in different countries, with 18 deaths.

But the French health ministry says it does not appear to be very contagious.

While it has been deadliest in Saudi Arabia, where 11 people have been killed by the virus, other cases have been reported in Jordan, Germany, Britain and now France.

The World Health Organisation on Thursday reported two new confirmed cases in Saudi Arabia.