The AJJF confirmed on Monday (April 13) that their managing director Soya Nakazato had tested positive for the coronavirus.

Nakazato's case was the ninth to emerge from the national federation, with eight other members having tested positive since April 4.

The number of cases has now risen to 17.

According to the Chinese news agency Xinhua, the AJJF have said 12 men and five women from their 39 staff members have contracted the virus.

All Japan Judo Federation President Yasuhiro Yamashita, an Olympic judo gold medallist, said earlier this week that the organisation's staff did not have close contact with the first infected person, or their family members, before April 1.

The statement suggested other individuals may have been infected during work or outside work hours by another person, with several employees reporting fevers until April 3.

The official said that with an incubation period of two weeks, it was difficult to determine the identity of people who were infected at the time.

He expressed hope the number of cases will fall due to reduced contact between people, promotion of hygiene measures and refraining from unnecessary travel.

A state of emergency is currently declared in Japan due to the coronavirus pandemic, which was extended nationwide on Thursday (April 16) through to May 6.

It is hoped the state of emergency will lead to an 80 per cent reduction in contact between people, as part of social distancing measures.

Non-essential workers have been asked to stay at home, while companies are being encouraged to operate remotely or stagger the shift patterns of staff to reduce the number of people commuting.

The pandemic has infected more than 2.2 million people worldwide with more than 156,000 fatalities.

The pandemic has also led to the postponement and cancellation of numerous sporting events, with lockdowns imposed in several countries to slow the spread of coronavirus.