A 33-year-old Australian man has been shot dead in New Zealand while having his campervan stolen by a suspect who remains at large, local police have confirmed.

Sean McKinnon, from south-western Victoria, and his Canadian girlfriend were sleeping at the Te Toto Gorge carpark in Raglan, on the west coast of the North Island, early this morning.

Police said a man demanded the key to the couple's campervan, before shooting the Australian. His partner, described as being "very shocked and distressed", managed to escape the gunman and alerted the police.

"At approximately 3:20am, police were notified that an offender had approached a van and shots were fired," Detective Inspector Graham Pitkethley said.

"At approximately 8:00am this morning, police located the van with the man's body inside."

Police said they found the van with the body inside some 80 kilometres away.

Armed officers have launched a manhunt across the Waikato district to find the gunman, who remains at large.

"Inquiries indicate that this was a random attack," Detective Inspector Pitkethley said.

"It is understandable and concerning to have an armed offender outstanding but I want to reassure the public we are working hard to identify and locate the offender. It is our absolute priority."

Te Toto Gorge Raglan, situated about three hours south of Auckland on New Zealand's west coast, is a popular coastal destination for walkers and hikers.

Detective Inspector Pitkethley said "the terrain where the vehicle was stolen is quite rough with a lot of bush around".

The Department of Foreign Affairs and Trade said it was "providing consular assistance" to the family of the deceased.

Raglan local Sue Marseglia said the incident has caught residents of the area by surprise.

"My daughter is at the local school and she's just rung to say that it was in lockdown earlier today," Ms Marseglia said.

"[I'm] in a bit of disbelief really, nothing like this happens in a small seaside town, it's quite unusual."

Police said the vehicle was a white 2017 Toyota Hiace campervan.

Stacey Davis from Apollo Motorhome Holidays, through which the van was said to have been rented, said the company was aware of the incident.

"We are co-operating with the authorities as the investigation continues and our thoughts are with the family at this time," she said.

The New Zealand Herald reported the Australian's girlfriend ran several kilometres to get help after the shooting.

McKinnon an 'honest, cruisy guy'

Corangamite Shire Councillor Simon Illingworth said he has spent countless hours surfing alongside the young man on the coast around Port Campbell, and has know him for about 15 years.

He said he is in disbelief about Mr McKinnon's death.

"I just can not believe that such a nice person could have their life finished like this," he said.

"He was just so lovely … such an honest, cruisy guy.

"He used to share waves in the surf and he was so courageous in big waves."

He said Mr McKinnon came from a close family and was a credit to his parents.

"To anyone who came down who decided to live down our way, Seany was the local they'd always talk about and say what a welcoming person he was," he said.

Councillor Illingworth said the last time he saw Mr McKinnon, he was being a "champion of the kids" on the Port Campbell pier.

"He was doing some sort of twisting somersault for the kids and I reckon there was 20 or 30 of them all clapping him as he did it," he said.

Corangamite Shire Mayor Neil Trotter said community members were stunned by Mr McKinnon's death.

"When they're people that you know and people you associate with, it hits home," he said.

Councillor Trotter compared the incident to the recent murder of Australian man Lucas Fowler and his American girlfriend in Canada.

"Unfortunately these type of incidents are increasing and it's mindless and senseless," he said.

"It just defies logic that people would do that to their fellow humans."

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