"He suffered from a bit of the old restless soul syndrome, he was a hard worker, a brilliant musician and an amazing surfer," she said.

Ms McKinnon said her brother was a very thoughtful person who spent his entire life helping people.

WHERE THE INCIDENT HAPPENED

"He was always a one to give you a hug and tell you that he loved you," she said. "He was a very gentle sort of soul with a good sense of humour."

Ms McKinnon said Sean's mother was heartbroken by the loss of her son.

"No parent wants to live to see their children pass away," she said.

"It's her worst nightmare."

UPDATE, 2.55pm: Long-time friend of Sean McKinnon, Wayne Such, told AAP Mr McKinnon was a "talented musician, genuine gentle man with a heart of gold".

UPDATE, 2.30pm: Corangamite shire councillor Simon Illingworth says the Port Campbell community is gutted over the tragic random shooting death of Warrnambool district musician Sean McKinnon.

Mr McKinnon, 33, was shot dead during a random attack in New Zealand on Friday morning.

"I knew him for years through surfing. He's just an awesome bloke, cruisy, honest, give you the shirt off his back sort of bloke," he said.

"I've known him for years, a couple of decades. I'm just gutted for him and his family. He was such a nice bloke."

Mr Illingworth said the Nirranda surfer and musician was well known around the Port Campbell area.

"Seanny Mac was always a legend. He would do somersaults off the Port Campbell pier with the kids. He always had time for everyone," he said.

"He was just a lovely bloke, liked to joke around and the kids that knew him will be absolutely devastated," he said.

EARLIER: The Warrnambool district man shot dead in a campervan in a random attack in New Zealand was a "lovable, knockabout Aussie guy" who "loved his surfing", according to mate Julian Smith.

Sean McKinnon, 33, of Nirranda, was killed while sleeping in a campervan in Raglan, outside of Hamilton, about 3am on Friday before his killer stole the vehicle and drove it for an hour with his body inside.

A manhunt for the gunman is under way.

"This is a tragic incident. Inquiries indicate that this was a random attack," Detective Inspector Graham Pitkethley told reporters in Hamilton on Friday.

Police said Mr McKinnon was sleeping in the campervan with his 32-year-old Canadian fiancee when the gunman fired a number of shots into the vehicle.

She escaped and fled to a nearby property to raise the alarm, while the gunman stole the campervan with the dying Mr McKinnon inside.

Police said Mr McKinnon's body was found in the stolen campervan, which was abandoned on Gordonton Road in Hamilton, about 80km away from the Raglan crime scene.

They want to hear from any witnesses who saw the campervan after the shooting - and Det Insp Pitkethley expects someone knows who killed Mr McKinnon.

"Due to the circumstances of the attack, it is likely that he has confided in members of his community," he said.

The gunman reportedly demanded the keys to the campervan before shooting Mr McKinnon "more than once".

Det Insp Pitkethley said police are working on the assumption the gunman is still armed, and all police in the Waikato area will be armed until further notice.

Raglan is a small town on New Zealand's west coast, south of Auckland.

Colin Chung from Colin's Cafe at nearby Whale Bay told AAP the area is a rocky coastline and provided some of the best surf in New Zealand, but it is off the beaten track for tourists.

He heard helicopters in the air about 6.30am but thought it might have been about a boat in trouble.

"It stayed in the air for a long time, maybe 45 minutes," he said.

The Department of Foreign Affairs and Trade said it was providing consular assistance to Mr McKinnon's family.