Hong Kong's Olympic athletes face a bigger threat from the tainted waters of Rio de Janeiro than the Zika virus, the city's former windsurfing gold medallist warned on Tuesday.

Lee Lai-shan is the southern Chinese city's only Olympic gold winner and a local heroine.

She expressed concern over the risk posed to windsurfers from the "very polluted" waters in the Brazilian city, which will host the Games in August.

"Our biggest hurdle is... the poor water quality. It's very polluted there. Once you fall sick you're done," Lee told the South China Morning Post.

Windsurfers will be competing in Rio's Guanabara Bay.

Brazilian authorities had promised to clean the natural harbour but even today, half of Rio's sewage pours in untreated.

Lee, who won windsurfing gold at the 1996 Atlanta Olympic Games, said that Zika would be less problematic.
"I think this virus is just another obstacle. Taking precautions to avoid mosquito bites would be enough," she told the Post.

Brazil has been most affected by the mosquito-borne virus outbreak that has spread rapidly through Latin America and the Caribbean.

While it causes only mild flu-like symptoms in most people, Zika is strongly suspected of a rapid rise in the number of children born with microcephaly -- abnormally small heads and brains -- to mothers infected during pregnancy.

Brazilian President Dilma Rousseff on Saturday launched a door-to-door "war" on mosquitoes that carry the virus and vowed they will not jeopardise the Games.
Source: AFP