A treasured piece of New Zealand art, recently re-discovered after being lost to the art world for 100 years, will go under the hammer next month.

The existence of a portrait of former Auckland mayor Sir John Logan Campbell was only known about as its painter - Louis John Steele - was pictured in his studio in 1903 sitting in front of it.

Since then, it's been privately owned for more than 100 years, and never pubicly exhibited.

Richard Thomson director of the International Art Centre has confirmed it will be offered at an auction of important and rare art in Auckland on August 8 after being contacted by its current owner.


He said it would be difficult to put a price on the painting but would range around $500,000.

"This would rank alongside some of Goldie's works in terms of importance and value and it could bring up to $500,000," Thomson said.

Steele, 44, arrived in Auckland about 1886 and set up a studio in Auckland and took a great interest in painting portraits of Maori chiefs and elders.

One of his first pupils was Charles Frederick Goldie and Steele had a great influence in the character and style Goldie displayed in his art which led him to become the most significant painter of Maori subjects in New Zealand art history.

"The location of the painting has been a mystery for more than half a century. No one knew where it was or even if it still existed so we were astonished and incredibly excited when a family member contacted us to sell it," Thomson said.

"This is more than a portrait of a man who made a huge contribution to the development of Auckland. It is a masterpiece and captures Sir John at Kilbryde, the mansion he built in 1881 at the site now occupied by the Parnell Rose Gardens.

"Sadly the house was demolished in 1924 so this painting, which portrays Sir John sitting at his desk with a view to Rangitoto Island, is an incredibly important window into Auckland's past.

"It is a national treasure and there is huge excitement that it has been 'rediscovered'."

The current owners have had the painting for over half a century, he said.

Steele and Goldie collaborated in 1898 to produce what is now considered the best-known history painting to be completed in New Zealand, The arrival of the Maoris in New Zealand, which caused a sensation when exhibited the year after it was completed.

It largely launched Goldie's career but it also led to a rift between Steele and Goldie after Steele resented the attention his former pupil was getting.

Other highlights of the sale are two watercolours by Frances Hodgkins, a 1918 work by Goldie, a collection from the estate of John Malcolm, the former president of the Queen Elizabeth II Arts Council, major works by Charles Blomfield, a rare oil by Isaac Whitehead and works from the Denis Savill Collection, Sydney.

Campbell died in 1912 and is buried on One Tree Hill. His body was taken from Kilbryde to One Tree Hill in one of the largest funeral corteges in Auckland history.