Six months after the Boxing Day tsunami, bodies are still being pulled from the water and from ruined buildings on the Thai island of Phi Phi.

The Buchan family, of Mt Maunganui, recently returned from two weeks' volunteering on the island, which featured in the movie The Beach before its palm trees and white sand beaches were laid waste by the deadly waves on December 26.

Nearly 1800 people, locals and tourists, perished on Phi Phi. The bodies of more than 1000 have never been found.

"There are so many people missing. They are there somewhere," says Kim Buchan.

During the time the 44-year-old, his wife Mary and their two teenage sons were on the island, six bodies were pulled from under a wharf. A woman's corpse was also discovered under a fridge.

Mr Buchan said divers retrieve bones from the water all the time and it is up to volunteers to deal with the remains. There are no undertakers on Phi Phi, so the volunteers place the remains in bags and take them to authorities for identification.

Mr Buchan said the huge task of rebuilding the island has also fallen to volunteers.

He said aid agencies helped in the tsunami's immediate aftermath but were not providing long-term assistance.

The Buchan family went to Phi Phi after reading about other New Zealanders helping with the cleanup.

They worked with a local charity, Hi Phi Phi (Help International Phi Phi), started by residents and tourists. Their main task was setting up a medical centre in the remains of a hotel.

Kim put his background as a plumber and gas fitter to use. Mary, a pre-school teacher, and Jacob, 13, cleaned walls and floors. Nathan, 14, helped divers clear debris off the ocean floor.

Before the tsunami, Phi Phi bustled with 2000 locals and an average 6000 tourists. Now, there are 1500 people all up, and more than 60 families remain in a refugee camp at Krabi, a 90-minute boat ride away on the mainland.

The lack of shelter, water and medical care on Phi Phi make it difficult for them to return. The Buchans say more volunteers are needed to get the island back on its feet, particularly tradespeople, doctors and nurses.

Tourists are also vital and the Buchans encourage people to go to Phi Phi.

Next month, Kim is back for two months for more plumbing work, and the whole family plan to return for three months next year.

The boys nod vigorously when asked if they want to return.

Kim and Mary have no worries about their sons having more time off school. Mary said going to Phi Phi was "the best social studies lesson they've ever had".

Kim said for the price of an airfare and not much more, the rewards were huge.

"It's far more than rebuilding things, it's rebuilding people's lives," he said. 

* Anyone wanting information on volunteering on Phi Phi Island can email Kim Buchan using the link below