A 22-year-old man who was arrested naked a few hours after Saturday's killings was charged in court with the murder of one of the victims, Hendrick (Hank) Van de Wetering, 51. Police said more charges may follow.
Stephen Anderson, an unemployed man from Wellington, showed no emotion as he appeared barefoot and in police overalls in Taumarunui district court, 20 miles from Raurimu.
Mr Anderson, bearded and with cropped hair, was remanded in custody to appear in Hamilton District Court on Wednesday. A psychiatric report was ordered. No application was made for bail or suppression of his name.
In sleepy Raurimu, the horror had not yet sunk in. "For this to happen, it's just devastating," said Julie Hurley."It's such a nice, quiet little place."
Families of the dead huddled in a classroom at the tiny local school, too traumatised to face the hordes of camera crews and journalists who were descending on their home in the wake of the carnage.
Saturday's killing is the fifth mass slaughter in the 1990s that has shocked New Zealand and undermined its image as a safe and peaceful place.
The gunman started his rampage on Saturday morning at the Raurimu Lodge, used by skiers frequenting Mount Ruapehu's ski slopes in winter, police said. New Zealand is now in mid-summer.
Aside from Mr van der Wetering, a local resident, police named the other victims as Neville Robin Anderson, 60, John Frederick Matthews, 28, Stephen Mark Hansen, 38, Anthony Gordon McCarty, 63, and Andrea Joy Brander, 52. All were from Wellington.
A police spokesman said none of the victims were related, but would not comment on whether the gunman was related to any of the victims.
Local residents and other reports had earlier said the victims included the father of the alleged gunman and other relatives, shot during a family gathering.
They said the alleged gunman had had a history of psychiatric problems.
Inspector Jeff Holloway told a news conference that the dead and the wounded were among 18 people at a gathering in Raurimu. He said it was too early to speculate on a motive.
The proprietor of a nearby motel, who declined to be named, said he understood one of the victims was a woman who had been walking along the roadside, apparently trying to hitch a ride. "One guy was going to pick her up, then he saw the guy with the shotgun and kept going," the motelier said. "He looked back and saw the woman getting shot to pieces."
One of the first to raise the alarm was Gordon Stewart. He came across a victim who had been shot in the head but had still managed to flee the scene. "He said he'd been shot and that other people had been shot," said Mr Stewart, who then went from door to door in Raurimu warning others to "get the hell out".
Unsure of where the gunman was, people sped away in cars and farm trucks and gathered several miles up the road before police arrived.
An inquiry into New Zealand's gun laws is already under way after the Port Arthur and Dunblane massacres in Australia and Britain last year, but it is not due to report until June. New Zealand has 11 times as many guns per capita as Britain and 60 per cent more than Australia. The police minister, Jack Elder, said he would review laws but did not wish to rush change for fear of getting it wrong.
A gun-policy researcher, Philip Alpers, and the opposition Labour Party said the killings reinforced the need for tighter gun laws.
Mr Alpers said New Zealand lagged behind Australia, Britain and Canada in tightening ownership controls.
"Australia, Canada and Britain - and most of the developed world - have left us far behind. What are we waiting for?" he said in a statement.