SYDNEY: Papua New Guinea police have rescued two women accused of sorcery who were about to be set alight, a report said Wednesday, days after a young mother accused of witchcraft was burned alive by a mob.

Sorcery cases have been a priority for authorities after the horrific case of a 20-year-old woman who last week was stripped naked, doused with petrol and set alight before a crowd, Highlands divisional police commander Teddy Tei told The National newspaper.

The woman, who was accused of causing the death of a six-year-old boy using sorcery, died after being tortured with a branding iron, tied up and set alight on a pile of rubbish in Mount Hagen in the Western Highlands.

The National said in the latest incident on Monday, also in Mount Hagen, two elderly women were tied to poles and people were preparing to set them alight over the death of an eight-year-old girl.

The girl's relatives believed the women caused the death of the child using sorcery but Tei said she had been "gang-raped and killed by two known suspects" and these suspects were part of the mob attacking the older women.

With them was a "glassman" -- a man who claimed to have supernatural powers and who had identified the luckless women as sorcerers and claimed they were responsible for the child's death.

Tei said police, who were tipped off by a witness to the incident near Kagamuga Airport, rescued the women and arrested 20 suspects.

He appealed to the public not to take the law into their own hands in the Pacific nation where there is a widespread belief in sorcery and where many people do not accept natural causes as an explanation for misfortune and death.

"What evidence do they have to produce to court for sorcery-related killing and torturing?" Tei said.

"It's just a belief."

Prime Minister Peter O'Neill has described as "barbaric" killings associated with sorcery and has instructed police to bring culprits to justice.

"Barbaric killings connected with alleged sorcery; violence against women because of this belief that sorcery kills -- these are becoming all too common in certain parts of the country," he said last week.

The government is encouraging families who are unsure about the cause of a loved one's death to take the body to a doctor to carry out a post-mortem.