The police is investigating allegations made by two former SMRT bus drivers that they were beaten up by police officers while they were held for questioning last November over an illegal bus strike.

An independent office within the police force, the Internal Affairs Office (IAO), has been tasked to investigate the allegations and will be contacting the pair over the alleged abuse.

Chinese nationals He Jun Ling, 32, and Liu Xiangying, 33, had claimed in a video that they had been slapped, punched and threatened while in police custody following the Nov 26 strike.

The video had been filmed by independent filmmaker Lynn Lee and posted on her website. It later made the rounds in cyberspace.

The IAO will also be contacting Ms Lee and other related parties to seek their help in investigations, said a spokesman from the Ministry of Home Affairs in a press statement on Tuesday.

Commenting on the matter for the first time, the spokesman said the ministry takes a serious view of the allegations against the conduct of police officers. "Such allegations must be taken seriously as it has a detrimental impact on public confidence and trust in the integrity of the Singapore Police Force."

Both He and Liu are charged with instigating the walkout by SMRT bus drivers from China - Singapore's first strike in 26 years. Another two, Gao Yue Qiang, 32, and Wang Xianjie, 39, also face similar charges.

The four men are among 171 drivers from China who took part in the strike on Nov 26 and the 88 who stayed away again the following day.