Two people who had contact with a Frenchman who is seriously ill with the new SARS-like coronavirus have fallen sick and been admitted to hospital, health officials in northern France said.

One is a patient who shared a ward with the 65-year-old man infected with the virus when he was in a hospital in the town of Valenciennes, northern France, at the end of April, and the other is a doctor who treated him there.

The 65-year-old carrier, who fell ill on his return from a trip to Dubai, has since been transferred to an isolated intensive care wing in a hospital in Douai, near the northern city of Lille, where he is in a critical condition.

The ARS local health authority said the two other men were in individual rooms in separate hospitals, one in Lille and the other in the nearby town of Tourcoing, and that tests had been carried out on both of them.

"They show symptoms which require a special infectious diseases consultation," the ARS said in a statement. "The results of the tests carried out on these two people will be known soon and will be made public."

As France reported the 65-year-old as its first case of the coronoavirus on Wednesday, the World Health Organisation said it would send experts to visit a Saudi hospital from which the virus has spread, killing seven people so far.

The French case brought the total number of known infections worldwide to 31, of which 18 resulted in death.

Coronavirus is from the same viral family that triggered the outbreak of Severe Acute Respiratory Syndrome (SARS) that swept the world from Asia in late 2003, killing 775 people.

Despite there being no evidence so far of sustained human-to-human transmission, health experts' concerns are growing over clusters of new cases.-Reuters