Hong Kong  - Five suspected mainland Chinese prostitutes were left screaming on board a speeding boat in rough seas after its coxswain jumped overboard during a police-chase in Hong Kong waters, a news report said Tuesday.

Marine officers had to leap on to the speedboat to stop its engine as the five women clung screaming on to the boat.

The incident, which happened late Sunday night, is the latest in series over the last month in which marine police have intercepted boats carrying illegal immigrants, said the report in the South China Morning Post.

A marine police spokesman said the boat was travelling at around 30 knots during the 10-minute chase and had tried to outrun the police boats after ignoring repeated orders to stop.

He said he believed the coxswain jumped into the sea about 5 kilometres from land, leaving the five mainland women on board with no one to steer the boat to detract attention so he could swim away.

The coxswain was later picked up from the sea and arrested for endangering lives at sea.

All six - the 28-year-old coxswain and his female passengers aged between 17 and 24 - were still being held for questioning Tuesday.

The Post said 1,144 prostitutes, mostly mainland women, have been arrested between January and April this year according to figures from the Immigration Department.

This compares to 3,787 prostitutes arrested in the whole of last year and 6,040 in 2006. (dpa)