After visiting the beach the woman and three men ate at a restaurant in Russell. Later in the day one of the men returned to Paihia with the woman to where she was staying.
Mr Masters said the woman fell asleep and when she woke her backpack had been stolen.
"She was left pretty much with what she was standing in.
"She was absolutely distraught. She was near the end of a big stay in New Zealand and due to leave on Saturday."
Her rental car was stolen from the motel between 4am and 5am yesterday. Police found it burnt out on the road to Elliot's Bay near Russell.
Mr Masters appealed to anyone who may have seen the Silver Toyota 2011 hatchback with the registration number of GEK762 to report to police.
He believed it may have been driven on the back roads to Russell via Waikare.
"Tourism plays an important part of the Russell and Paihia communities. This poor woman is taking back bad memories of the Bay of Islands and good memories of the rest of New Zealand that will get shared worldwide," Mr Masters said.
"Some lowlife has taken advantage of this woman."
He said she was used to travelling alone and liked to talk with locals where she visited.
Anyone with information should contact Russell police on 09 403 9090.
The theft comes after two Swedish tourists had most of their possessions stolen when their vehicle was broken into near Dargaville on January 22.
Four German tourists also had their plans to tour New Zealand ruined after all their clothes and two passports were stolen from their campervan in Auckland last month.
Offers of support have flooded in since the theft was publicised.
