Hundertwasser Art Centre campaigners are counting down to opening day in Whangārei.
Visitors will be welcomed on 15 December - the late artist's birthday.
Friedensreich Hundertwasser was one of the most famous European artists of the 20th century.
He died in 2000 and was based near Kawakawa for the last decades of his life.
He designed the centre for Whangārei in 1993 but the district council struggled to secure a site, funding, and public support.
The proposal later won a referendum in 2015 and has cost more than $33 million to build, largely from philanthropic donations and $18.5 million from the Provincial Growth Fund.
It will soon be home to about $16 million worth of Hundertwasser's art, the only permanent collection outside of Vienna, as well as the Wairau gallery, the world's first gallery dedicated solely to contemporary Māori art.
Wairau Māori Gallery board chair Elizabeth Ellis (Ngāpuhi, Ngāti Kuta, Ngāti Porou Te Whānau a Takimoana, Ngāi Tane) said the two galleries inside would be showing "completely different things" but Hundertwasser's world views and te ao Māori had a lot in common.
"Underlying all that is the splendid philosophy, this belief in harmony of nature and creativity of all mankind."
Prosper Northland Trust chair Andrew Garratt spent three years volunteering to make the project a reality.
He told RNZ seeing the building so close to completion was "pretty exciting stuff".
"I kind of feel like the whole way we did it will be unique. It will be difficult to see how a building could arouse such passion again."
Andrew Garratt and fellow volunteers raised more than $16 million for the project.
They also recycled materials from Whangārei's former harbour building, including chipping more than 35,000 bricks.
Richard Smart, the New Zealand representative for the Hundertwasser Foundation, has overseen quality control at the site.
He worked for the Austrian-born artist for eight years.
"He loved New Zealand. He loved the nature. He loved the tranquillity out at his place. It was a refuge. He came to New Zealand to take a break, to immerse himself in nature."
The Hundertwasser Art Centre is covered with an afforested roof with more than 4000 plants, and a tower topped with a cupola covered in thin gold leaf.