Bali: Australian man Joshua James Baker could be jailed for up to 15 years after being named a suspect for allegedly bringing a mixture of marijuana, tobacco and prescription-only drugs into Bali.

Mr Baker, 32, was handed over to police after being apprehended at Ngurah Rai airport on October 8 with an alleged 28 grams of marijuana and 37 pills of diazepam, a prescription-only sedative.

Joshua James Baker in custody in Bali with the alleged drugs found on him.

Bali police spokesman Hengky Widjaja said Mr Baker, who was born in Mount Isa, Queensland, had been named a suspect but remained under doctor's observation.

Naming someone a suspect in the Indonesia justice system means authorities believe they have enough evidence for charges to be filed, which does not take place until the case is before the court.