Indian badminton star Saina Nehwal wants a longer Olympic qualifying period. (Photo: AFP)

Indian badminton star Saina Nehwal on Sunday urged the sport's world body to extend its Olympic qualification period as the spread of the coronavirus forces the cancellation or postponement of competitions.

The German Open, which was to be held between March 3 and 8, has been cancelled while the China Masters and Polish Open have been postponed and dropped from the Olympic qualifying process.

The Badminton World Federation has refused to extend its qualification deadline from April 28 for the Tokyo Games, which kicks off in July.

Nearly 3,000 people have died and about 87,000 infected worldwide since the virus was first detected late last year in the central Chinese city of Wuhan.

"It will be unfair for most of the players who are really close to qualifying for Olympics 2020," Nehwal, the first Indian badminton player to win an Olympic medal with a bronze at the 2012 London Games, tweeted.

Her husband Parupalli Kashyap, who also represents India, said he was concerned that qualification events were being cut.

The loss of tournaments poses problems for many players including two-time Olympic champion Lin Dan, who needs a rapid rise up the rankings to win a place on the Chinese team.

"We all had seven events starting from Spain Masters until the Singapore Open and few have the Asian Champs too," Kashyap wrote on Twitter.

"It will be completely unfair for so many athletes who are on the borderline of qualification at this moment... I hope all the athletes have a fair chance to qualify for the Olympics."

The top 16 players who make it to the Tokyo Games will be decided through their performances at coming tournaments, including the All England Open (March 11-15) and the India Open (March 24-29).