Watch on problem inmates
Management of troublemakers at violence-prone Ma Po Ping prison has been strengthened.
Officials also have stepped up training in handling conflicts and other emergencies at the Lantau prison after a scuffle in December.
In a report to legislators, the Security Bureau is adamant the fight between two groups of inmates in the dinning hall was subdued without using unnecessary force.
'Apart from using their hands to separate the prisoners, officers had not applied any other force to stop the fight,' legislators were told.
The incident on December 28 has prompted a review of the population composition, with the inmates reshuffled or removed to other prisons to ease the tension.
Investigations showed the fight was a revenge attack on mainland prisoners after two local inmates were assaulted the day before.
The mainlanders accused the pair of cheating on lap counts in a race in the assembly yard.
They were later attacked by eight mainlanders. Three officers and 10 prisoners were slightly injured.
The bureau admitted prejudice and distrust between locals and mainlanders had contributed to the clashes.
Correctional services officers were accused of using excessive force in suppressing a similar scuffle at Ma Po Ping last summer.