Asia-Pacific countries should boost their healthcare capacity and fully vaccinate their people to prepare for a surge in Covid-19 cases fuelled by the Omicron variant, officials at the World Health Organization (WHO) said on Friday.

First detected in southern Africa last month and dubbed a "variant of concern" by the WHO, scientists are still gathering data to establish how contagious Omicron is, and the severity of the illness it causes.

It has been reported in at least two dozen countries and started gaining a foothold in Asia this week, with cases reported from Australia, Japan, South Korea, Singapore, Malaysia and India. Many governments have responded by tightening travel rules.