A Steinway grand piano carved with Maori patterns is part of Michael Parekowhai's installation at this year's Venice Biennale. Adam Gifford talks to piano restorer David Jenkin about the instrument's journey to Italy.

The piano going to Venice was part of New Zealand's cultural history even before Michael Parekowhai took to it with chisels. Restorer David Jenkin says the Steinway concert grand was first sold in London in 1926 and shipped to New Zealand half a century ago.

Inside the body was pencilled a dedication: "Dear friends, may this beautiful instrument bring you happiness and inspiration. All my love, Lili Kraus, London, Christmas 1959."

Kraus was a Hungarian-born pianist who wound up in New Zealand in 1945 after three years in a Japanese prison camp in Indonesia. She toured the country extensively before moving to England in 1948, and her concerts would have been the first time many New Zealanders heard live performances of Beethoven, Mozart and other greats of the classical canon.

"Michael has this thing about pianos, as a statement of high Western art," Jenkin says.

"This piano was probably selected by Lili from Steinway in London for broadcasting or one of the town halls. When I first came across it, it belonged to a jazz pianist in Whangarei.

"Then Michael turned up with it [in 2002] and said, 'Can you do anything?' I said if you're serious, it will need some serious work and he said, 'I am serious'."

There is a tradition of art case pianos, where material is added to the outside then carved.

"But they are mostly ugly," says Jenkin. "Michael's aesthetic is around the shape of the piano."

That meant the carving needed to be in the existing rim, but when it came back to Jenkin's Glenfield workshop in 2006, about a third of the mass was gone, which need to be returned for strength and to restore tone.

"We got oak and mahogany, put it through the thicknesser, and laminated it in alternate 2mm horizontal bands around the inside of the piano. It was a nightmare of a job, but we understood why he had to do it that way."

The cast iron frame was trimmed 10mm all round to fit in the new frame on a redesigned mounting system, and a new soundboard installed.

Because it is pierced by carvings, the lid does not reflect sound in the way of normal grands, creating a more diffuse effect.

"I have to say I think it's a thing of spectacular beauty. I love it, and I love that it's a Steinway concert grand and I love that it kind of looks tribal," Jenkin says.

He won't reveal how much his part of the job cost, but "it's the most extensive and expensive piano restoration ever done in New Zealand".