PHNOM PENH: Cambodia reported on Monday its first cases of the highly contagious UK variant of the novel coronavirus, after three foreigners who arrived from overseas tested positive while in quarantine.

The Southeast Asian nation of about 16 million people has reported among the lowest number of coronavirus cases, recording less than 500 infections and no deaths, although a rare cluster emerged in November. Most of its cases have been imported.

The health ministry said the cases with the UK variant were two people from India and one from China, all of whom had been isolated.

The B1.1.7 variant, first found in Britain, is highly transmissible and its discovery prompted a tightening of travel restrictions globally among countries keen to keep it at bay.

Cambodia's health ministry also warned the public against complacency, saying people "seem to forget the enormous risk of transmission" at mass gatherings like ceremonies, parties, weddings and festivals, where health measures were not being followed.

"Cambodians must not underestimate the potential for rapid transmission and severity caused by COVID-19 on the human body," it said.

"The high prevalence and severity of the disease can happen in our country at any time, any circumstance, anywhere if individuals do not protect themselves."