China's Hong Kong Special Administrative Region (HKSAR) will ban all passenger flights from the United Kingdom from Thursday over concerns of the Delta variant of COVID-19, the HKSAR government announced on Monday.

The UK will also be specified as "extremely high-risk," and people who have stayed there for more than two hours will be barred from boarding flights to Hong Kong, the government said.

The restriction is due to the "rebound of the epidemic situation in the UK and the widespread Delta variant virus strain there, coupled with a number of cases with L452R mutant virus strains detected by tests from people arriving from the UK," the authorities said.

The government added that existing restrictions on other places regarded "high-risk," including Brazil, India, Indonesia, Nepal, Pakistan, the Philippines and South Africa, will continue to be effective.