A group of four women, along with their 13 children and grandchildren, are at risk of being murdered in Papua New Guinea after being accused of witchcraft, a missionary says.

Anton Lutz, a Lutheran missionary in PNG's Highlands, told Radio Australia's Pacific Beat that while details are still coming in, the church, government and NGOs were trying to see if they coud help.

He said a "witch-hunter" pointed them out when villagers were investigating a measles outbreak that has killed several people.

"A witch-hunter, as it were, travelled from a village called Wanakipa ... to the place where these women were and to identify them," he explained.

He said their lives were in serious danger.

"This is happening in the Hewa language [group], which extends between the northern part of Hela province and the western part of Enga province," Reverend Lutz said.

"It's a very large group and they are well known for murdering women."

'Over 20 accused witches killed in recent years'

Reverend Lutz said he knew of at least 25 women killed over the past 10 years after being accused of sorcery in the western part of the Hewa language group, with no arrests being made.

He said it was difficult to get the authorities to help, because the community was only accessible by one airstrip and reports had only just emerged about the imminent killings.

"It's an extremely remote part of this country," he said.

"We're still trying to notify the authorities and we're waiting for calls back from the police right now."

But the missionary said accusations of sorcery and retaliatory violence against women were not unique to remote, undeveloped areas in PNG.

He pointed to last year's killing in Papua New Guinea's third-largest city, Mount Hagen, where Kepari Leniata, 20, was burnt alive after being accused of sorcery.

The young woman was from an area believed by many in PNG to be a hotbed of witchcraft.

"And she had run away from her village because she had been accused of this witchcraft thing and she escaped here," he said.

"But she was actually murdered [in Mount Hagen] based on accusations from [her hometown], which is where this story is unfolding.

"So it's a very real risk that sort of extends right through the highlands."

Accusations becoming more widespread

Reverend Lutz said the accusations of sorcery were becoming more widespread.

"For instance, I live in the Enga province, in the eastern part of it, and there are no traditional beliefs about this kind of witchcraft," he said.

"But, because of the movement of people ... those who have never believed in these kinds of things before are now hearing these stories and believing in them."

Last year, a conference on sorcery in Melanesia heard the belief in the power of others to cause harm using supernatural powers was deeply ingrained in the region.

"We consider it a very troubling phenomenon that really goes to the heart of the international human rights framework as a human right violation against women's right to life," said Nancy Robinson, UN High Commissioner for Human Rights regional representative.

"A right not to be tortured and also to lead a life without violence.

"These are issues that we are aware of exist in many countries, but her feel that it is inadmissible that by virtue of cultural practices, women's right to life is being violated."