Equestrian has become one of the trickiest events for organizers of the 2008 Beijing Olympics.

The event was moved hundreds of kilometers south of the Chinese capital to Hong Kong, where animal diseases are less common than in Chinese mainland. But some still worry how the horses will fare in Hong Kong's tropical heat and the impact of isolating the sport from the main competition.

Organizers of the equestrian event hope to test out logistics and weather in a small-scale trial competition next weekend.

Seventeen horses and their riders will arrive from France, Britain and the U.S. among other nations, joining 20 local horses in dressage, jumping and eventing competitions from August 11-13.

"The main purpose for the trial is to let the horses acclimatize to local weather conditions, so they can get an idea of the humidity and adjust," said Christopher Yip, a spokesman at the company set up for the Hong Kong equestrian events.

The International Equestrian Federation had opposed the relocation of the 2008 equestrian events to Hong Kong, complaining that it would hurt the sport by separating it from the main Games in Beijing, about a four-hour flight away.

But the International Olympic Committee accepted the proposal by Beijing organizers, who said Hong Kong is free of quarantine problems and equine diseases common on Chinese mainland.

It's not the first time the Olympic equestrian events have become problematic. When Melbourne hosted the 1956 Olympics, the events were held thousands of kilometers away in Stockholm, Sweden, because of strict quarantine laws in Australia.

Beijing said 17 equine diseases are prevalent in Beijing and other mainland Chinese cities. It also said it had "major difficulties" establishing a disease-free zone. In contrast, Hong Kong has a long history managing race horses.

Hong Kong has a small population of horses concentrated in training schools and racecourses, making it easy to monitor their health, Jolly Choi, a spokeswoman for the government's Agriculture, Fisheries and Conservation Department, said.

Incoming horses will be isolated from local race horses throughout their stay to minimize any risks of contamination, Choi said. The horses must also undergo tests both upon arriving in Hong Kong and before they leave the territory, she said.

Horse racing is a major industry in the city, and equestrian organizers and observers say they are confident in the experience of the overseeing body, the Hong Kong Jockey Club, which is providing the main venues for the equestrian competitions.

Li Tak-nang, a Jockey Club spokesman, said the body prides itself on its expertise in comprehensive horse welfare, including everything from accommodation to stabling to transportation.

"Our experience in taking care of race horses is more than enough for handling equestrian horses," he said.

Hong Kong's sweltering summer heat and humidity, however, remain major problems. Last August, the average maximum temperature in the territory reached nearly 31 degrees Celsius (88 Fahrenheit), and this year has been even hotter.

Yip said organizers will use up to 40 metric tons (44 short tons) of ice per day for to make ice water to cool horses down.

The trial event next weekend will be held in the early morning and evening to avoid the worst of the heat. Large misting fans have been installed in air-conditioned stables, and the Jockey Club has also converted an air-conditioned indoor stadium into a training arena for the event, Yip said.

Lucy Higginson, editor at the London-based Horse and Hound magazine, said British riders and owners approve of the facilities in Hong Kong.

"I just hope the weather will be a little forgiving," she added.