Police divers are scouring waters around Bruny Island in Tasmania for a Melbourne woman who vanished while on a holiday two weeks ago.

Rachel Funari, a US citizen who had been living in Victoria for several years, was last seen at a holiday home on the rugged island, south of Hobart, where she left her backpack and tent.

The 35-year-old's younger sister Nicole and three of Ms Funari's friends were due to arrive on the island today to be briefed on extensive search efforts in the past two weeks involving up to 60 rescuers and a police helicopter.

Yesterday, a police cadaver dog failed to find any trace of Ms Funari on hiking tracks around the island and the base of large cliffs in Fluted Cape, near Adventure Bay.

Inspector Doug Rossiter said an excavator was brought in when the dog detected a buried item, however the remains were those of a wallaby.

He said the land search had been scaled back today and focus would shift to the water, where four divers would work in two teams at the base of the cliffs.

"We are confident we have thoroughly searched an extensive area where inquiries indicate it is most likely Ms Funari was headed,” he said.

Ms Funari's friends raised the alarm when she missing a flight home two weeks ago.

Police said the Monash University graduate had been couch-surfing with a man in Hobart when she met a father and daughter with a house on Bruny Island, and travelled there with them.

The father and daughter returned to the mainland the following day and left Ms Funari on the island.

Police say no foul play is suspected in her disappearance.

The US citizen has lived in Melbourne for several years, where she worked as a freelance writer.

She is described as being 165 centimetres tall with brown curly hair and a fair complexion.

Inspector Rossiter said police had received several possible sightings of Ms Funari, which were being investigated.