The outbreak of Delta variant cases in humans linked to the shop worker prompted tests on hundreds of animals, with 11 hamsters showing up positive.

That has brought a pet rodent clampdown on Chinese-ruled Hong Kong, which is following the mainland's zero-tolerance approach to COVID-19 even as much of the world shifts to living with it.

The territory's Health Secretary Sophia Chan stressed at a news conference that there was no evidence domestic animals can pass the disease to humans, but authorities were anyway acting out of caution to ban imports and sales of pet rodents.

"Pet owners should keep a good hygiene practice, including washing hands after touching the animals, handling their food or other items, and avoid kissing the animals," Agriculture, Fisheries and Conservation Department director Leung Siu-fai Leung also told reporters.

"If citizens are raising hamsters, they should keep them at home. Do not bring them out."

Hundreds of samples were collected from animals also including rabbits and chinchillas, but only the hamsters have tested positive so far.

"To be careful, we will take preventive measures against any transmission possibilities that we cannot rule out," said Chan.

After three months without local transmission, Hong Kong has dozens of new cases in humans this year, triggering fresh restrictions on flights and social life.

Thousands of people have been sent to a makeshift government quarantine facility. Most of the new cases are of the highly-contagious new Omicron variety, though the cluster traced to a pet shop worker was Delta.

Leung said about 2000 hamsters in 34 pet shops and storage facilities would be put down "humanely". Anyone who purchased a hamster after December 22, 2021 should hand them over to authorities for culling and not leave them on the streets, he added.

A hotline for COVID-19 enquiries related to hamsters is also being set up.

Australian Associated Press