A gang of mainland women are using the promise of sex to trap and rob their victims in Yau Ma Tei, police warn.
At least six men have been lured since the beginning of February to short-stay love hotels and stripped of their cash and valuables, but no sex was involved.
The group of five or six women aged between 30 and 40 prey on elderly men, police said.
They pose as prostitutes and ply the streets of Yau Ma Tei in the afternoon.
Once one of them secured a client, she would take the victim to a nearby guesthouse, supposedly for sex.
She would ask him to take a bath first and while he was in the shower, would steal his money and valuables such as watches and escape, police said.
Each victim lost between HK$1,000 and HK$2,000 in cash and valuables, he said.
Police believe the women are two-way permit holders and are allowed to stay in Hong Kong for sightseeing.
"We believe they are controlled by a gang who helps them hire a room in such guesthouses," the officer said.
Love hotels in the area charge about HK$250 a day for a room.
Detectives are checking if similar cases have been reported in other districts.
Police are understood to have stepped up inspections and licence checks at the short-stay hotels.
In a separate case, officers are looking out for a middle-aged man who has scammed nine eateries, known as cha chaan teng, in Tsim Sha Tsui and Wan Chai out of about HK$15,000 since February.
The man would telephone the woman workers, mostly cashiers, at the shops, pretending to be their boss in urgent need of money, police said.
"The employee was usually instructed to take the cash immediately to his friend who would be waiting outside the eatery across the street," an investigator said.
As each case involved HK$1,000 to HK$2,000, the employee did not check with her employer, police said.
Officers believe that the caller and the man who picked up the money were the same person, who spoke Cantonese with a mainland accent.
Police's figures show there were 6,923 reports of deception last year, a 12.9 per cent rise from 6,134 in 2011. There were 5,652 cases in 2010.