A Japanese delegation of 28 travelled to Almaty for the Asian Karate Championships, with more than half testing positive for COVID-19 after returning home ©Getty Images

The Japanese team who competed at the Asian Karate Championships in Almaty are at the centre of a COVID-19 outbreak, with up to 16 cases reported by the Japan Karate Federation.

Japan topped the medals table at the tournament held in Kazakhstan, which concluded last Wednesday (December 22).

However, the Japan Karate Federation has confirmed that more than half of the delegation of 28 has now tested positive for COVID-19 - 13 of the 19 athletes and three of the nine staff.

A total of 11 initially tested positive at the airport after returning to Japan, with eight of these cases confirmed as the Omicron variant, which is more transmissible.

The other three are also "suspected" to be infected with Omicron, but one of the individuals has since returned a negative polymerase chain reaction (PCR) test for two consecutive days.

Four further positive test results were returned on December 25, and since then two more asymptomatic or mild infections have been confirmed.

The Japan Karate Federation said it was continuing to conduct regular PCR tests and follow quarantine rules.

Individuals who have tested positive are following instructions from health authorities, while those who are negative are voluntarily quarantining until January 7.

Kyodo News reported that the team was in a bubble for the Asian Championships, and that World Karate Federation general secretary Toshihisa Nagura said the measures in place "were thorough" after inspecting the competition venue.

More than 400 athletes from 23 nations were involved at the Asian Championships.

The Omicron variant has already impacted the sporting calendar in Japan, including the cancellation of the Grand Prix of Figure Skating Final in Osaka due to restrictions on international travel.