Health experts are worried a new superbug may be festering on Australia's doorstep, as a drug-resistant tuberculosis outbreak in the northern Torres Strait continues to worsen.

Key points: Daru Hospital tuberculosis ward full, many patients being treated in community

Daru Hospital tuberculosis ward full, many patients being treated in community PNG Government has not yet delivered on promised $20 million funding

PNG Government has not yet delivered on promised $20 million funding People moving into bush in search of food and water making it harder to access health centres

More than 160 of the 15,000 people living on the island of Daru, near the PNG–Australia border, have drug-resistant tuberculosis — the highest rate in the world.

The PNG Government has not yet delivered on promised funding for an emergency response, and a prevailing dry weather pattern is intensifying the problem, as sick people can no longer travel for treatment.

"We're seeing an outbreak of drug-resistant tuberculosis that we haven't seen the scale of before," Brendan Crabb from the Burnet Institute, a communicable disease research centre in Melbourne, said.

Poverty, overcrowding and people failing to complete their treatment are adding to the problem, but researchers are now wondering if those are the only factors.

"So, is that an environmental factor that's allowed that to happen, or more worryingly, is that a bacterial factor?" Professor Crabb said.

"Is there something about this organism that makes it a superbug?"

Daru Hospital's Australian-funded tuberculosis ward is full — and the chief executive of the hospital, Orpah Tugo, said there were still many cases the hospital could not take.

"I can't [take any more patients] at the moment, and it's very serious now that they're with their family in the community," she said.

"The spread will go on. It's very contagious."

El Nino drives community inland

Health authorities are supervising people's treatments in their own communities, to take the pressure off the hospital.

"They are diagnosed [at the hospital] and then they are sent back to the community, so that we in the community can take care of these tuberculosis patients," Sonia Madjus from World Vision said.

The PNG Government has not yet delivered on promised funding to help combat tuberculosis. ( ABC News )

Many patients live in remote areas of this undeveloped PNG province, where the only way to get around is by water.

The current El Nino dry weather is making it even harder for health authorities.

It means people are moving further into the bush, or cannot travel to health centres for treatment.

"People are not where they're supposed to be because [they're going] in search of food and water," emergency response coordinator Ninkama Moiya said.

"So, it just makes it more difficult to access them in terms of following up on treatment."

Daru's situation has provoked an international response, but the PNG Government has not met its own $20 million commitment.

"The money that has been allocated to fight this problem has not been released. We've been waiting for a while now," Dr Moiya said.

While they wait, the disease continues to spread — throughout communities right on the brink of the Australian border.