The Centre for Health Protection (CHP) on Sunday urged the public to avoid eating raw oysters after five more people fell ill with food poisoning.

The CHP said food poisoning cases have surged in recent weeks. In late December, health officials saw an average of one case per week. By January, that had jumped to four a week, and in the first week of February cases surged to 27.

Health authorities said the majority of cases, which affected a total of 108 people in the past three weeks, are linked to norovirus.

The latest cluster involves three men and two women. They experienced diarrhoea, abdominal pain, vomiting and fever after eating raw oysters at Chef's Cuts in Wong Chuk Hang.

They are currently in stable condition.

Officers are investigating the restaurant and its raw oyster supplier, Jeton International Food and 88 Investment Holdings, following the outbreak.

The CHP has ordered the supplier to suspend the sale and supply of raw oysters, and instructed businesses to immediately stop selling any oysters from that company.

The CHP's controller, Edwin Tsui, warned that raw and partially cooked oysters are a high-risk food.

"As the Lunar New Year holiday is approaching, members of the public have more opportunities to have parties with food delivery services or hotpot. To prevent food poisoning, apart from maintaining personal hygiene, they should also consume thoroughly washed and cooked food," he said.

"For shellfish, the shells should be well scrubbed and the internal organs be removed before consumption."

Tsui warned that norovirus, besides causing food poisoning, can also lead to acute gastroenteritis.

He added that norovirus activity is on the rise in popular travel destinations including Japan and South Korea. He urged travellers to be vigilant and pay attention to hygiene to minimise the risk of being infected.