Norwegian health authorities on Wednesday announced the first case of coronavirus in the Nordic nation in someone who returned from China last week, but said the patient was not "in danger".

"The person is not ill, they are in good health and do not present any symptoms," Line Vold, an official at the Norwegian Institute of Public Health, told reporters. "We think it is very unlikely that they have infected" others.

Routine tests had given a "weekly positive result" and detected traces of the new coronavirus, the institute said.