A man who posed as a cop to rob three Indian nationals of more than $1 million was sentenced to eight years' jail and 12 strokes of the cane on Wednesday.

Mohammad Ansari Abdul Hussain, 34, pleaded guilty last month to two of 10 charges - gang robbery of $917,657 and impersonating a police officer at Dunlop Street on Sept 10 last year.

He robbed Mr Gulam Hussain Jalaludeen, 32, with his four accomplices, Mr Magesan Ramasamy, 34, Mohammad Faizal Ajmalhan, 30, Arunachalam Laksmanan, 34, and Chinnaya Antony Samy, 35, whose cases are pending.

He was cleared of a charge of having a handcuff. Seven other charges, including two gang robbery and two attempted robbery, were taken into consideration. The total amount involved in all the charges was $1.3 million, of which $899,320 have been recovered.

Citing multiple aggravating factors, Deputy Public Prosecutor Sanjiv Vaswani asked for a stiff sentence of no less than eight years' jail.

He said Ansari, a former police national serviceman, had donned a police uniform in committing the offence, bought paraphernalia for the heist and concealing his identity.District Judge Lim Keng Yeow said in his oral grounds that a critical aggravating factor was that the offenders acted as cops and donned police uniforms.

"The very symbol of law and order in our society was brazenly turned into a tool of criminality, audaciously employed to achieve the opposite of what it stands for. This cannot be taken lightly,'' he said.

He also noted that the offence was carefully planned for, preparations were highly meticulous, and the victims were specifically targeted. The entire operation was designed and executed with a high level of sophistication and apparent professionalism far unlike a simple street gang robbery offence committed on the spur of the moment by immature novices.

The maximum penalty is 20 years' jail and caning.