He was a private and qualified machine gunner in the New Zealand Expeditionary Force's Wellington infantry regiment when he landed on the beach at Gallipoli on April 25, 1915 with his brother, Matt.
By May Dunn had contracted pneumonia, and after hospital treatment and was returned to duty, still ill. While on sentry duty, he fell asleep after being warned not to. He was discovered asleep by an officer and was brought before a field court martial.
Dunn pleaded guilty and a sentence of death was laid down, but the judgement was remitted on the grounds of his health and previous good conduct.
Three days after his reprieve, his unit was part of the attack on Chunuk Bair. He was shot through the throat and died instantly.
There is no known grave but his name is on the Chunuk Bair (New Zealand) Memorial and on the Tinui War Memorial.
His brother Matthew survived the war and was a machine gun instructor at the Featherston Camp in 1918, with the rank of sergeant major.
Aratoi Museum director Alice Hutchison said they were "very much inclined" to bid for the medals, although there were no guarantees when it came to auctions.
Ms Hutchison said she wanted to get more advice from Masterton military historian Neil Frances, based at Wairarapa Archive.
"We're very keen to look further into it. We're planning a big Featherston Camp exhibition, and we're definitely looking for objects from the community.
"It would be very exciting to get these medals, but we can't guarantee to be the winning bidder."
From her time in America, it was common for wealthy benefactors to bid on similar items, and donate them to museum.
"Our resources are limited; if there was a friendly benefactor, keen to support the local museum, that would be willing to buy it?"
She said they could also be competing against bigger museum, like Auckland, or Te Papa.
Noble Numismatics' military historian John O'Connor, speaking to the Time-Age from Sydney, said he hoped the medals would get back to New Zealand.
"I think they should be in a museum," he said.
He said the owner was a person who had owned them for several years, and did not have a family connection.
"I hope you can get them back to your community, and at a reasonable price."
The value was arbitrary, and could go up.
"I don't know how much it will sell for," he said.
"In the last auction, we had a bugle up for $15,000, and it sold for $58,000 - I guess a few people wanted it."
He said it was common in Australia for wealthy people to buy war memorabilia and donate it to a museum.
"It happens quite regularly with the Victoria Cross."
Noble Numismatics turns over $A3-6 million a year in auction items, and are the largest dealers of coins, medals and banknotes in Australia.
People can view the medals at noble.com.au, which are appearing as Lot 3635 in Sale 108 at the State Library of New South Wales, Sydney.
Bids can be sent in on line, or people can bid live on line or by phone.
To view, go to www.noble.com.au/auctions/lot?id=336074
Date of Birth: 22 November 1888
Obituary:
Wairarapa Daily Times, 10 September 1915 "Private "Jack" Dunn, of Masterton, who is reportedly in to-day's casualty list as "believed to be killed" was a very popular resident of the town. He was about 26 years of age, and was a son of Mr M. Dunn, farmer, of Whakataki. For years past he had followed journalistic pursuits, and was a member of the literary staff of the "Wairarapa Daily Times" when he enlisted in the Main New Zealand Expeditionary Force. Previous to that he had been on the staffs of the "New Zealand Times" and Levin "Chronicle". In athletic circles Private Dunn was well and favourably known. He was a well-known runner. He had been a member of the Wairarapa Amateur Athletic Club, serving on the management committee of the club, and was secretary of the Masterton Harrier Club at the time he enlisted. He took a keen and active interest in football, and had played for the Red Star Club. He had also played a good deal of cricket and hockey. The deceased was a very promising journalist, and had a bright career before him. He wrote several interesting letters to the "Wairarapa Daily Times" on the doings of the New Zealand troops at the front, the last appearing in our columns on Wednesday. The news of his death will be received with feelings of deep regret throughout the Wairarapa, and the sympathy of a wide circle of friends will be extended to the relatives in their bereavement."
