Letters from a German naval cadet at the centre of one of New Zealand's best known prisoner of war break-outs more than 90 years ago have surfaced in Auckland.

Albert Paulsen - believed to have been captured when New Zealand took control of the former German Samoa during World War I - was a POW on Motuihe Island in the Hauraki Gulf, and later on Somes Island in Wellington Harbour.

His letters to sweetheart Emma Meyer - which went on sale this week - talk about his desire to be reunited with her, and his fellow prisoners' attempts to keep the boredom of captivity at bay.

"It must have been a pretty easy number, really, considering they could have been in Europe, fighting in the trenches," says Auckland dealer/collector Warwick Paterson, who is preparing the items for sale.

Paulsen spent about four years in custody, most of it on Motuihe, and it was there he met the infamous German naval officer Count Felix von Luckner.

As commander of the Seeadler (Sea Eagle) in 1916 and 1917, von Luckner sunk 14 allied ships in the Atlantic and Pacific.

He was interned on Motuihe after being tricked into surrendering in Fiji.

Not content to spend the war on picturesque Motuihe, von Luckner and a group of prisoners - including Paulsen - stole the camp commander's motor boat and fled in December 1917.

There are no pictures of Paulsen, and the only physical description of the 24-year-old comes from a Truth newspaper story from the time of the escape.

He is described as having light brown hair and blue eyes, and was clean shaven - at least he was the last time the guards saw him.

Paulsen would have been a handy man to have in the escape as he spoke English so well he "might easily pass for an Englishman".

The authorities finally caught up with the fugitives on the Kermadec Islands, and Paulsen was sent to Somes Island.

The letters, part of a wider collection of postal memorabilia, came to Mr Paterson from the estate of American collector George Brenan. It is likely he acquired the items in Europe.

There are five letters and five multiple-choice prisoner of war postcards from Paulsen for sale. The letters are on the market for around $3000.

One letter sent from Featherston Military Camp in early 1919 is priced at $3750.

Paulsen had a brief stay at Featherston after leaving Somes Island and was repatriated to Germany at the end of the war.

One of the collection's rarest pieces is an envelope sent by German prisoner of war K. Rudolph on Motuihe to fellow German Klaus Klink, another prisoner of war in New South Wales.

It has an asking price of $4950.

The letter it once held has been lost, but the envelope is important, as it is one of the only examples of communication between prisoners of war held in different countries.

"In 40 years, I have never seen anything like this. They are most desirable things," says Mr Paterson, who expects interest in the pieces from European collectors.