Australian officials say friends of Perth teenager Liam Davies, who died after drinking a methanol-laced cocktail in Indonesia, must return to the region to formally register the case with police.

Mr Davies, 19, became critically ill after celebrating New Years Eve with cocktails in a bar on the Gili Trawangan Islands off Bali.

His family has called on Indonesian authorities to investigate his death.

The Department of Foreign Affairs and Trade says it has been told witnesses who were with Mr Davies at the time of the incident must speak with police in person before an official investigation can be launched.

Staff from the Australian Consulate General in Bali are assisting two of Mr Davies' friends to return to Lombok.

DFAT says it has no jurisdiction in Indonesia and no authority to investigate any alleged crime.


Mr Davies parents say their son's condition deteriorated in an Indonesian hospital after he was misdiagnosed with a brain aneurism.

The teenager was flown to Sir Charles Gairdner Hospital in Perth but later died.

Mr Davies father, Tim, says Indonesian authorities need to launch an inquiry into the incident.

"We hope that the Indonesian authorities aggressively investigate not only Liam's death, but the many events where people have died or been made seriously ill," he said.

"Medical staff need to be trained on the signs and treatment associated with methanol poisoning."