A police union leader and a lawmaker warned activists who terminated their bail they could be rearrested at any time.
Activists arrested recently during several demonstrations have adopted the practice of terminating their bail as a protest over lengthy police investigations and what they claim are 'political' arrests.
The protesters want police to decide whether or not to bring charges against them within 48 hours, the maximum time a person can be held without being charged.
Benjamin Tsang Chiu-fo, the newly elected chairman of the Police Inspectors' Association, said he was aware that some protesters might be using this action to achieve certain political aims or arouse concern.
Police can keep suspects on bail for months before deciding if they will be charged.
They can also extend the bail period if they need more time for their investigations.
He said bail was set to ensure that suspects would appear at a police station on a certain day to facilitate inquiries.
On June 4 some 67 of 113 people arrested on March 6 after a demonstration against the budget marched to North Point police station, with about 200 supporters, to terminate their bail. When clashes ensued after they blocked a road, a further 53 were arrested.
Although police could not charge detainees for breaching bail conditions, they could confiscate their bail and issue a 'holding charge' to send the person to court after the bail period, if they believed the detainees would repeat the offence, Tsang said.
Lawmaker James To Kun-sun said bail represented a deal between arrestees and the police and each party had the right to terminate it.
He said police could still continue their investigations and rearrest the suspects at any time once they had enough evidence.
'The activists may have earned a high-profile and a brief victory, but in reality they still live under the pressure of being arrested at any time, in any place,' To said
Bobo Yip Po-lam, one of the activists who initiated the mass termination of bail on June 4, admitted the protesters did have a political message to convey and people were fully aware of the risks. 'Our decision not to co-operate with the police indicates that our action is just and their arrest is unreasonable,' she said.
She said in some cases, police extended bail periods to scare activists off joining social movements.
A police spokesman said there were no statistics on how many activists had terminated bail recently. He said the police respected the right of peaceful assembly.