A group of archaeology researchers were taken hostage by heavily armed men demanding a cash ransom.

A group of archaeology researchers, including a professor from New Zealand working for an Australian university, two local university graduates and a programme coordinator, were taken hostage by heavily armed men demanding a cash ransom.

The group were on a field trip to the remote village of Fogoma’iu in the Mount Bosavi region, near the boundary of Southern Highlands and Hela provinces.

Earlier this week, the captors released a woman who was part of the group.

“It took us a while but the last three has been successfully returned,” Prime Minister James Marape said in a statement on Sunday.

Police said they were returning to the capital Port Moresby with the three freed hostages Sunday afternoon, where Marape would greet them.

The group were taken hostage at gunpoint last Sunday in a remote and densely forested region.

Police had been negotiating with the hostage takers, who initially demanded a ransom of $1m — an enormous sum in one of the Pacific’s poorest nations — before dropping the asking price and abandoning a 24-hour deadline.

Marape said the hostages had been freed after “covert operations” and the original ransom demand had not been met, but did not provide further details.

“We apologise to the families of those taken as hostages for ransom,” Marape said. “To criminals, there is no profit in crime. We thank God that life was protected.”

Papua New Guinea’s highlands are a sprawling expanse of jungle-cloaked hills where the central government and security forces have little sway.

In recent years, the regions have seen an increase in tribal warfare and the proliferation of weapons.