The parents of seven were volunteers with medical aid organisation Australian Doctors International and based in North Fly District, Western Province.

They used a banana boat to travel along the Fly River to villages and set up clinics in school buildings, native houses and under trees.

Dr Docherty said they saw up to 50 patients a day and treated children as young as four with muscular-skeletal and back problems, as well as adults with abscesses, infections, tuberculosis, leprosy and acute chest infections.

``Everyone smokes and cooks on fires in their huts,'' Dr Docherty said.

``There are no chimneys and so the smoke just circulates inside the thatched roofs.

``Some of these villagers hadn't had a visit from a medical patrol in over a year and had been told they needed to go to another centre for further treatment, but they couldn't afford it.''

Dr Docherty said it was frustrating and upsetting to know the patients were unable to travel on the river to receive medical attention and were not supported by government assistance.

But the couple did what they could, by training health workers and speaking to villagers about malaria and hygiene.

``We'd go through what malaria is, how you get it, how to avoid getting it and how important hygiene is,'' Dr Docherty said.

``Things like washing your hands after using the bathroom and before preparing food.''

Occupational first-aid trainer Mr Mason said gastro-intestinal illnesses spread easily between family members.

``We take for granted having clean, running water in Australia but in New Guinea it has to be carried long distances,'' he said.

``It's a precious commodity and is used for washing and drinking, not so much for keeping clean.''

Mr Mason also helped schools and parishes to fix their computers and community radios and Dr Docherty taught obstetrics to hospital staff.

``We have an awful lot back in Australia and everyone needs to give something back,'' Dr Docherty said. ``We like the challenges a trip like this presents.''

The couple return to Papua New Guinea for six months in February 2011.