PORT MORESBY: A cholera outbreak in Papua New Guinea continues to spread, with fears 100 more villagers may have died.

Last week, Canberra announced it would make an extra $A500,000 available to battle cholera as PNG officials reported the disease spreading inland after an outbreak on PNG's side of the Torres Strait was contained.

Cholera on Daru, a tiny island off the coast of PNG's Western Province close to Australia's Cape York, has struck down more than 800 people.

Villagers travelling by sea to Daru and other islands in the mouth of the Fly River had aided the rapid spread of the deadly bacteria that causes diarrhoea-like symptoms.

Travel between Australia's Torres Strait Islands and neighbouring PNG has been restricted, with hundreds turned away in an effort to contain the deadly cholera outbreak.

The World Health Organisation (WHO) along with Australian aid agency AusAID have been regularly flying in medical supplies in a much-needed relief effort.

An AusAID spokesman in Port Moresby told AAP the situation in Daru is now under control after several weeks of high incidence.

"There have been 32 confirmed deaths in Daru caused by cholera and 870, mostly mild, cases of acute watery diarrhoea.

"Although the data is not entirely reliable, it now seems that the South Fly District (of PNG) reports possibly 400 cases with around 100 deaths," a spokesman said.

The increase in reported cases over recent days is due to better information and increased information flows, a direct result of the assistance provided by Australia, he said.

Australia has provided $A1.7 million in assistance to combat the outbreak, which is said to have killed 100 people since it was first reported on PNG's northeastern coast in September last year.

Cholera usually makes people only mildly sick, but up to 10 per cent of patients develop a severe illness.

It is transmitted by water contaminated by bacteria from an infected person or food contaminated by dirty water, soiled hands or flies.