Former WWII dam buster pilot Les Munro, who died this week, had offered to auction his medals and pass on the funds for the upkeep of a London memorial that honours his comrades.

Brave and principled but compassionate and unassuming - Les Munro was the sort of Kiwi character many talk about but few live up to.

With his death in Tauranga on Tuesday New Zealand lost one of the greatest of a generation that put service before self.

In conflict he bravely gave service to his country in the one of the most daring raids of WWII with the Dambusters of RAF 617 Squadron.

Supplied Les Munro leaning out of the cockpit of a Lancaster, which he flew on the Dam Busters raid.

In peace he gave decades of service to his small community and then stood up to help when his wartime mates were in danger of being forgotten.

Prime Minister John Key said New Zealand had "lost a remarkable man who led a remarkable life" with the passing of Munro.

"I was honoured to meet Les Munro in person when I attended the presentation of his medals to Motat (Auckland's Museum of Transport and Technology) just a few months ago," Key said.

"His contribution to his country and his generosity will not be forgotten."

Munro's son, Graeme, said his father died "peacefully, after a very short illness".

It is understood he died peacefully, surrounded by family.

Out of the 19 commanding officers who flew on the raid on the Ruhr Valley in May 1943, Munro was the last remaining. He lived in Tauranga.

In March this year, Munro offered to sell his war medals to help fund the upkeep of a London memorial that honours his comrades.

However, British businessman Lord Ashcroft made a donation to the RAF Benevolent Fund; in return, Munro withdrew his medals from auction and gave them to Motat.

Peter Wheeler, chief executive of the New Zealand Bomber Command Association, said he'd had dinner with Munro about a month ago and he seemed fine.

However, the former World War II pilot had been in hospital for the past two weeks, he said, being treated for heart problems.

Munro was patron of the NZ Bomber Command.

Wheeler said Munro was "perhaps a little embarrassed" about the attention he got as a Dambuster, and said the generosity with his medals epitomised his character.

"He accepted the role he was sort of cast into in that, he did it not for himself, or for his own personal glory or honour.

"Everything he did was for the greater good of the people he flew with - and that's pretty much what he did all his life."

Munro was awarded several honours, a spokesperson for the Royal New Zealand Air Force said.

After the war he was officially NZ413942 Squadron Leader J L Munro and had a Distinguished Service Order and Distinguished Flying Cross.

"Les Munro was a distinguished and highly-decorated officer who throughout his lifetime epitomised the values of the Defence Force through his courage, commitment and comradeship," Chief of Air Force, Air Vice-Marshal Mike Yardley said.

"Les made a lasting impression and his valour will remain an inspiration to those serving in the air force, both current and future."

Motat chief executive Michael Frawley said he was "incredibly sad" about Munro's death.

"But, from the museum's perspective, we're very honoured to be able to tell his story so his legacy lives on, because he's one of New Zealand's - and indeed England's - great heroes."

Frawley had met Munro several times.

"He gave you the impression that he was going to live forever. It's really sad news. But what a guy, what a hero," Frawley said.

Motat was fundraising for a travelling exhibition that would tell the stories of Munro and other members of Bomber Command.

A NZ Bomber Command Fund was being set up through the Perpetual Guardian Foundation and the long-term plan was to add an archive to keep memorabilia in one place.

The World War II Dambuster raids involved bombers from the RAF's 617 Squadron dropping bouncing bombs - so-called because they skipped on water until they hit a dam and exploded - on three dams in Germany's industrial heartland of the Ruhr Valley in May 1943.

Munro, who went on to be mayor of Waitomo, piloted one of those planes, but had to turn his Lancaster bomber back after it was hit by flak over Holland.

It took 67 years after the raids for the Bomber Command Memorial to be unveiled in London's Green Park, commemorating men from the command who were killed.

In a March 2015 interview with stuff.co.nz, Munro called the delay a "travesty".

"Because of that long delay, a large percentage of the aircrew that survived the war have not lived to see the day when the sacrifice of their comrades was finally recognised in a tangible form," he said.

After World War II, Munro farmed in King Country then set up his own Te Kuiti farm before getting into local politics.

Waitomo Mayor Brian Hanna said Munro served as mayor of the district for five terms, from 1980 to 1995.

"He's certainly been a guiding light for the Waitomo district. He was held in the highest regard by everyone."

Hanna said Munro was "one of New Zealand's great heroes".

"It's a very sad day in our history."

Hanna said Munro set up the relationship between Te Kuiti and its sister city, Tatsuno in Japan during his final years as mayor. The relationship is 20-years-old this year.

A memorial service for Les Munro will be held at the Classic Flyers Aviation Museum in Jean Batten Dr, Mt Maunganui on Saturday, August 8 at 1.30pm, Graeme Munro said.

Donations can be made in Les' honour to the Waikato Bay of Plenty Cancer Society and the NZ Arthritis Foundation.