Activists have called on the police to make public their guidelines governing how male officers should physically handle female protesters.
The call from the Civil Human Rights Front followed remarks yesterday by secretary for security Lai Tung-kwok that police could decide the matter on a case by case basis.
The front's vice-convenor, Icarus Wong Ho-yin, called Lai's remarks shocking.
"If the rules are so loose, it can easily lead to abuses of power," Wong said. "It will be very dangerous if Lai agrees that the police can do whatever they like according to their assessment of a situation. Do we accept that the police can exercise their power so freely? The force should make clear its guidelines, if any, on the handling of female protesters by male officers."
Earlier in the day, about a dozen activists from the Defence of Hong Kong Freedom and three pan-democrat legislators - "Long Hair" Leung Kwok-hung, Leung Yiu-chung and Gary Fan Kwok-wai - staged a protest at the government headquarters in Admiralty over the police's use of force in handling students at a recent demonstration. They demanded Chief Executive Leung Chun-ying and Lai offer an apology to the students.
About two dozen student activists staged a protest at the Caritas Institute of Higher Education in Tseung Kwan O on Thursday, when Leung was there to officiate at a ceremony.
On Leung's departure, the activists occupied a road, blocking Leung's car and demanding that he meet them to discuss universal suffrage. The students were carried away by police after a 20-minute stand-off.
One protester, Ho Kit-ming, later said she was grabbed by a male officer from behind as she tried to approach Leung's car. She discovered it was a male officer only the next day when she saw a picture in the newspaper.
"When I learned that it was a male officer, I felt uncomfortable, offended and harassed," Ho said. She said her breasts were touched and questioned why a policewoman had not been sent to handle her, as one was standing nearby.
Lai declined to specify the circumstances under which it could be considered acceptable for a male police officer to grab a woman protester from behind.
"We mainly have to see the actual situation to decide what action to take at that moment. So, we cannot treat different matters in the same way," he said.
Deploying women officers depended on the overall demands being made on the force, he said. The proportion of male and female officers assigned to handle a demonstration would then be adjusted as needed.
He said the police had established procedures to deal with demonstrators and complaints.
But the police would not comment on their guidelines for operations.
Referring to Thursday's protest, a spokesman said that after issuing repeated warnings, officers took action against the demonstrators to stop illegal behaviour. He said the police respected the public's right to freedom of expression and assembly but stressed the need for order to be maintained.
At the end of 2011, there were 28,200 police officers in Hong Kong, one in five of whom were women.