Some 80,000 tourists are stranded in the southern Chinese beach resort of Sanya, after authorities declared it a COVID-19 hot spot and imposed a lockdown.

The restrictions came into force on Saturday morning, as authorities sought to stem the spread of COVID-19 in the city on tropical Hainan Island. There were 229 confirmed cases on Friday and an additional 129 on Saturday.

China's ruling Communist Party sticks steadfastly to a “zero-COVID” approach that is increasingly at odds with the rest of the world. A recent outbreak in Shanghai spread so widely that authorities locked down the entire city, China's largest, for two months, trapping millions of people and dealing a blow to the national economy.

Railway authorities banned all ticket sales in Sanya while all flights were also canceled on Saturday.

Tourists wanting to depart Sanya have to test negative for the coronavirus on five PCR tests over seven days, authorities said.

Meanwhile, hotels will offer guests a 50% discount during the lockdown period, a city official said during a news briefing.

The lockdown comes during a peak tourism season in Sanya, which is famous for its resorts and beaches.