(Adds details of online response)

HONG KONG, Feb 28 (Reuters) - Hong Kong authorities said on Friday they quarantined a pet dog of a coronavirus patient after its nasal and oral samples tested "weak positive" for the virus, though they added they did not yet have evidence that it can be transmitted to pets.

The dog did not have any symptoms.

The Agriculture, Fisheries and Conservation Department (AFCD) said it would conduct further tests to confirm if the dog had been infected with the virus or if the samples were the result of environmental contamination.

"At present, the AFCD does not have evidence that pet animals can be infected ... or can be a source of infection to people," it said in a statement.

The dog will be put under quarantine for two weeks.

The World Health Organization website says so far there has been no evidence that companion pets can be infected with the coronavirus.

Several users on Chinese social media site Weibo called for people not to spread reports that could lead to pets being harmed for fear of infection.

"This really is a pretty irresponsible piece of news," said one user. "It's very likely it could bring disaster to many pet dogs and cats on the Chinese mainland."

Hong Kong has reported 93 confirmed cases of coronavirus infections in humans, and two fatalities. (Reporting by Marius Zaharia; Editing by Himani Sarkar)

Our Standards: The Thomson Reuters Trust Principles.