The spread of a new coronavirus could throw "cold water over the growing momentum of the 2020 Games," Tokyo Organising Committee chief executive Toshiro Muto said.

Key points: Vaccines for the virus will likely not be ready by the start of the Summer Olympics

Vaccines for the virus will likely not be ready by the start of the Summer Olympics Japan Sports Agency has started examining the impact on preparations of athletes

Japan Sports Agency has started examining the impact on preparations of athletes The Chinese Formula 1 Grand Prix may not go ahead this year because of the coronavirus threat

"I am seriously concerned … I hope this will be resolved as soon as possible," Mr Muto said at a meeting in Tokyo with the organisers of the Paralympic Games.

Japanese Government officials including Prime Minister Shinzo Abe have said the Government would work hard to minimise any impact from the virus outbreak on the Games, which start on July 24.

The death toll from the flu-like virus that originated in China's central city of Wuhan has passed 500, as two US airlines suspended flights to Hong Kong following the first fatality there and 10 cases were confirmed on a quarantined Japanese cruise ship.

Vaccines against the virus probably will not be ready by the start of the Tokyo Summer Olympics, a professor who looked at health risks ahead of the Games said earlier, adding he hoped there was enough time to build defences.

Saburo Kawabuchi, head of the athletes' village for the 2020 Olympics, said he hoped the games would proceed smoothly, free from the virus.

Separately, Japan Sports Agency has started examining the impact of the virus on preparations by athletes for the Olympic and Paralympic Games, NHK reported.

Chinese F1 Grand Prix under threat

Daniel Ricciardo won in Shanghai in 2018. ( AP: Andy Wong )

Meanwhile, Shanghai sports authorities have recommended the suspension of all sporting events in the city due to the coronavirus outbreak, casting further doubt on whether the Chinese Formula 1 Grand Prix will take place.

The fourth grand prix of the season is scheduled for April 19 in Shanghai.

The race was expected to be on the agenda at a Formula 1 Strategy Group meeting amid increasing speculation that it could join the growing list of sports events already postponed or cancelled.

The Shanghai Sports General Association called on sports organisers to "strictly abide by the requirement of the Shanghai Sports Bureau to stop organising sports events during the epidemic".

It said, in a statement, that all sports events should be suspended "until the epidemic is over".

Some Formula 1 insiders hold out little hope of the race happening.

"I'm sure they [Formula 1 and the FIA] will take the necessary due diligence before making any commitment about either delaying or postponing or cancelling the race," said Red Bull team boss Christian Horner ahead of the meeting.

"So we have to trust their judgement, their knowledge."

The last Formula 1 race to be cancelled was the Bahrain Grand Prix of 2011, due to months of social unrest in the Gulf kingdom.

This year's calendar has a record 22 races, leaving little chance of any rescheduling. Russia, whose race is in September but has previously been held in April, has already ruled out a date swap.

The outbreak has affected numerous international sports events in China. Among them was the world indoor athletics championships scheduled to be held in Nanjing on March 13-15, which have been postponed until next year.

The all-electric Formula E motor racing series has abandoned plans for a race in Sanya next month.

An LPGA Tour golf tournament has been moved to next year, while women's football matches have been moved to Australia.

Reuters