"This is a tragedy. It is an unbelievable, unthinkable and atrocious criminal act that must be dealt with swiftly and severely," Tokura said in a statement.
"We will use all available resources to bring the killers to justice," he added.
Prime Minister James Marape said many of the victims lived in his electorate. "Today is one of the saddest days of my life," he said on social media.
Marape blamed a police shortage in Hela for the lawlessness.
"How can a province of 400,000 people function with policing law and order with under 60 policemen ...?" he wrote.
"To all who have guns and kill and hide behind the mask of community, learn from what I will do to criminals who killed innocent people, I am not afraid to use strongest measures in law on you," he said, referring to the death penalty.
Tribal violence is common in Papua New Guinea's interior, where villagers avenge relatives in retaliation known as payback.
Hela official Rex Humbi said the latest violence was part of a tribal war that had been waged for more than 15 years.
"The people that got killed were innocent women and children," he said. "The police do go and investigate. They have the authority, of course, but don't have the firepower" to bring the killers to justice.
The killers were possessed by Satan and "feed on the soul, or the spirits, of the innocents that have been lost," Humbi said.
- AP