Police arrested a 56-year-old man on suspicion of violating public decency on Friday after he allegedly poured an unknown liquid on a number of female passers-by.

Officers said they had received reports from nine females, aged 16 to 32, between January 20 and February 18, claiming they had been splashed from behind with an unknown liquid near Mong Kok MTR Station and in the area of Sai Yeung Choi Street South.

After investigating, police said they detained the suspect in Causeway Bay, as he was in the process of splashing the liquid from a thermos onto a 17-year-old female.

They added that the liquid was currently undergoing laboratory testing, but that the victims had described it as being lukewarm, odourless, and light-coloured.

The man, who is understood to be a construction worker, is currently being held for further questioning.

Police have appealed for any other victims, or witnesses, to come forward.