The influx of high-powered weapons and an insufficient police force have emboldened tribal violence in Papua New Guinea's Highlands, humanitarian and community groups have said, in the wake of a brutal massacre in Hela province this week.

Key points: Pregnant women and children were reportedly among those killed in the village of Karida

Pregnant women and children were reportedly among those killed in the village of Karida Officials say the local police force is ill-equipped to take down tribal "warlords"

Officials say the local police force is ill-equipped to take down tribal "warlords" An influx of modern weapons is creating more casualties in decades-old tribal conflicts

At least 16 people, mostly women and children, were killed in the village of Karida on Monday in the most recent outbreak of a decades-old tribal conflict in the Pacific nation's mountainous and remote Highlands region.

Police announced a final death toll of 18 people, which included the unborn babies of two of the women who were believed to have been pregnant.

Ahmad Hallak, the head of mission for the International Committee of the Red Cross (ICRC) in Papua New Guinea, told the ABC the use of guns had led to more causalities in tribal disputes.

"It's an open secret that the prevalence of modern weapons is definitely adding fuel to the flames," he said.

"Tribal violence is an historical phenomenon; it's been going on for time immemorial. In the past, though, using bows and arrows [and] spears, much more limited battles would take place.

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"With the presence of modern weapons this is no longer the case, and we are seeing humanitarian consequences very similar to Iraq, Syria Afghanistan."

The motive behind the killings remains unknown, though officials suggest it could be an act of retribution for a recent tribal dispute that left seven dead.

"It's an unfortunate situation," Hela Governor Philip Undialu told the ABC.

"The relatives of some of the deceased take the law into their own hands and tried to attack enemies at will. And that has escalated into a massacre of innocent women and kids."

Thousands of people are displaced every year in PNG due to tribal violence.

Mr Hallak said the targeting of women and children is also increasingly common in tribal conflicts, where the fighting can be "indiscriminate".

"Unfortunately, women and children can often be targets and can suffer the consequences of tribal fighting," he said.

"Unfortunately, the likelihood of more massacres like this are high."

He said communities affected by violence wanted it to stop and local initiatives were in need of support to address the root causes, like unemployment, substance abuse and election-related violence.

Sixty police for 400,000 people

Poor resourcing in Papua New Guinea's police force has contributed to tribal violence, observers say. ( AAP: Lloyd Jones )

The case has highlighted poor resourcing for police, with Prime Minister James Marape questioning how a province of 400,000 people could function with fewer than 60 officers.

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Mr Marape said on Facebook that the perpetrators could face the death penalty and issued a warning to the killers: "I am coming for you."

Damien Arabagli, head of the Hela Gimbu Association, said his community group had been calling on the Government to increase police numbers.

He described the killers as "warlords" and said they were unlikely to ever be held to account by the region's small police presence.

"They know who [the killers] are and they are afraid to go and hunt them down," Mr Arabagli said.

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The Royal PNG Constabulary released a statement via Facebook stating that a 30-men team comprising soldiers and local police will be sent to the area "to stop any further violence and capture the killers".

Acting Police Commissioner Francis Tokura was quoted in the post promising to make an assessment and "decide on a long-term approach to address the issue in Hela".

"This is a tragedy. It is an unbelievable, unthinkable and atrocious criminal act that must be dealt with swiftly and severely," commissioner Tokura was quoted as saying.

"We will use all available resources to bring the killers to justice."

Efforts were hampered by a lack of road access to areas dominated by jungle and rainforest.

"The police have the willpower, with the army as well, but to hunt them down you're looking at no network coverage of mobile phones and then you come to a jungle where no cars can go through," he said.

He called on PNG's Pacific neighbours to help.

"We are calling for intervention by Australia or New Zealand forces on the ground, with [the] UN. People have been subject to killings, this is not the first one," he said.

"We had the same killings the previous year, and the previous year, and they just get covered up again. This has been going on, and the people are living in fear."

'They are not human'

The murders mark a dark development for PNG, where superstitions about sorcery exist and sometimes result in violence.

Rex Humbi, an officer from the Hela Provincial Administration, described the killers as "possessed".

"They are not human. They are part human and part Satanic-possessed," he said.

"You can shoot them with guns — live bullets — but they do not die … They feed on the soul or the spirit of the innocents that have been lost."

He said while police did investigate such incidents, they were ill-equipped to stop the violence.

"They are the authority, of course, but they don't have the fire power," he said.

Police embroiled in organisational tussle

PNG police have not given an official response to the ABC regarding the massacre, with the force's top brass currently tied up in a political stoush.

On Friday, the country's police minister, Bryan Kramer, sacked police commissioner Gari Baki and two of his deputies.

No explanation was given at the time, but in the 24 hours afterward Mr Kramer told local media that the officers' contracts had expired and they were over the public service retirement age.

The Government has appointed new senior officers to act in their roles, but former commissioner Mr Baki is seeking a court order to prevent the PNG Government from making the new appointments.

While the tit-for-tat continues between the Government and the ousted police bosses, the organisation is struggling to get information out to the country, because there is no-one to approve what will be released to the public.