A Cambodian court has convicted three foreigners, including an Australian woman, for trying to smuggle 2.2 kilograms of heroin out of the country and sentenced them to prison terms ranging from 23 to 27 years.

The 41-year-old Australian woman, Ann Yoshe Taylor, and a 19-year-old Frenchwoman, Charlene Savarino, were arrested in September at the Phnom Penh International Airport after police found the heroin in their luggage.

The Phnom Penh Municipal Court on Wednesday sentenced Taylor to 23 years and Savarino to 25 years in prison, and and ordered both to pay $US12,500 ($A13,524) fines.

A Nigerian accomplice, 23-year-old Precious Chneme Nwoko, was subsequently arrested in Phnom Penh and was sentenced to 27 years in jail.

All three deny wrongdoing and say the luggage belonged to someone else.