Police on Thursday arrested another man in connection with the murder and dismemberment of socialite Abby Choi, bringing the total number of arrestees to six.

They accused the 41-year-old, who works at a yacht company, of trying to help one of the suspects flee Hong Kong by sea, adding he was offered hundreds of thousands of dollars.

A superintendent of the force's Kowloon West regional crime unit, Alan Chung, said the man, surnamed Lam, was arrested in Sheung Wan and will be detained overnight.

"What I can say is that the case is still under active investigation. As to when, how or where the victim was killed, that's our main focus of the investigation," he told reporters, adding that police do not rule out making further arrests.

Meanwhile, Chung said police have ended the search operation at a landfill for the victim's body parts, saying officers were trying to find two or three bags out of some 4,000 tonnes of refuse.

Among the five people previously arrested, three of them have appeared in court charged with murder, with another to face a count of perverting the course of justice.

The fifth person is suspected of hiding one of the suspects, but was earlier released on police bail without charge.