Michael McCrea, 48, who was sent to Singapore from Australia after losing an extradition battle, was sentenced to the maximum 10 years each for two counts of culpable homicide not amounting to murder.

He received an additional four years for causing evidence to disappear in relation to a murder, his lawyer Kelvin Lim told AFP.

McCrea was "very shocked" by the length of the sentence, Lim said.

He and his client had expected a maximum 16 years in prison, back-dated to June 2002 when McCrea and his girlfriend Audrey Ong were arrested by Australian police, Lim said.

The couple had fled to Australia after the killings in January that year.

McCrea admitted on Monday to strangling his driver Koh Nai Guan, 46, and using a plastic bag to suffocate Lan Ya Ming, 29. Court was told that McCrea had a fight with the driver who had used the word "slut" to describe McCrea's Singaporean girlfriend, local radio reported.