The manhunt for members of a gang behind the violent robbery and rape of an Australian woman in a holiday villa in Bali has been widened to include the neighbouring Indonesian island of Lombok.

A senior Bali police officer involved in the investigation said on Friday that a man arrested earlier this week in connection to the attack had since provided further details of the whereabouts of the three other members of the gang still at large.

While having admitted to taking part in the robbery, the man identified by the initial "A" maintains that another member of the group, identified by the initial "G", was behind the brutal attack in the early hours of the morning on April 27.

The Perth woman was attacked after being woken by an intruder in her room at Villa Damais in Kerobokan where she was staying with family.

She was forced to open a safe in her room, before being raped while a knife was held to her throat.

The attack occurred as other members of her family slept nearby.

"During questioning he swore that he did not rape the victim and offered to meet with her," a police spokesman told AAP on Friday.

"We're taking A to Lombok to help us catch the other three perpetrators, especially G."

Police earlier this week released a sketch of the man they believe was responsible for the rape.

They have also said his description matched that of a man believed to have carried out previous rapes in Bali.

Under Indonesian law, a rape conviction carries a maximum penalty of 12 years in jail.

If convicted, the gang members would most likely be sent to Kerobokan jail, where a number of Australians are housed including Schapelle Corby and the Bali Nine.