A union representing Hong Kong lifeguards says they will go on strike on Tuesday over a staff shortage that is being exacerbated by an influx of mainland tourists to pools and beaches.

"There has been a shortage of lifeguards in recent years... the influx of swimmers from mainland China has further increased the workload, making colleagues suffer unspeakably," Hong Kong and Kowloon Lifeguards' Union said in a statement on Monday.

Some 10 per cent of the city's 1,900 lifeguards are expected to go on strike, forcing the closure of several beaches and public pools at the height of the summer season, a union spokesman told AFP.

Union vice chairman Alex Kwok Siu-kit says the government cut lifeguard numbers by some 30 per cent in 2004 for economic reasons and they could not cope with a surge in the number of mainland visitors, with some visiting on a "one-day swimming tour".

"They think water quality here is better, and the safety standards," he said.

Mr Kwok says some of the visitors failed to observe basic hygiene or behaved improperly.

"Some of them urinate everywhere and jump into the pool without wearing swim suits, or bring food to the venue. They don't have the same personal hygiene and safety standards."

Hong Kong, a city of seven million, has seen a massive surge in tourists from mainland China following Beijing's relaxation of travel restrictions and their growing affluence.

The Hong Kong Tourist Board has said it expects 59 million visitors this year - of these it is estimated 45 million will be from the mainland.

Tensions between citizens of Hong Kong and mainland Chinese have soared in recent years, fuelled by an influx of visitors blamed for a host of problems, from a shortage of hospital beds to soaring property prices.

AFP