Authorities in Papua New Guinea have arrested 29 members of a suspected cannibal cult accused of killing seven people before eating their brains and making soup from their penises.

The accused are alleged to have been part of a 1000-strong group which was formed to take on suspected witch doctors.

They believed their victims had all been involved in 'sanguma', or sorcery, and that they had been demanding sex and money from villagers in return for exercising their spiritual powers.

A Madang Police Commander, Anthony Wagambie, confirmed reports that the cult members had eaten the victims' brains raw and had made soup from their penises.

“They don't think they've done anything wrong; they admit what they've done openly,” Wagambie said.

The group claimed witch doctors had begun charging large fees of 1,000 kina or $475 for casting out evil spirits and providing other services.

The accused also claimed the alleged witch doctors had begun demanding sex as payment.

The cult members believed that by eating the witch doctors' body parts they would attain their spiritual powers, and become bullet-proof.

Reports claim that there could be between 700 and 1000 cult members in several remote PNG villages in the northeast interior.

The killings prompted police raids in the village of Biamb last week resulting in the 29 arrests.

The case has now been adjourned until the 17th of August so that the authorities can gather further evidence.

Whilst under the colonial rule of Australia the traditional culture of PNG retained isolated pockets of cannibalism into the latter part of the 20th century - human flesh was known as "long pig".

In recent years there have been a number of cases of alleged witchcraft and cannibalism.

Last year a man was reportedly found eating his newborn son during a sorcery initiation ceremony.

In 2009 reports claim a woman was burnt alive at the stake in the Highlands town of Mount Hagen - the crime was also thought to be related to sorcery.

According to reports in The National newspaper 28 women and men appeared in court on Tuesday charged with murder - it was not clear what had happened to the 29th cult member.

Police have said they are gathering more evidence regarding the cannibalism before any charges are made relating to those crimes.

Murder is punishable by death penalty in Papua New Guinea.

Police Commander Anthony Wagambie said there could potentially be more arrests this weekend, maybe of another 100 people.

He also said that four of the victims had been murdered very recently, possibly even last week.

He added that none of the victims' remains had been found,