A $90 million restoration and expansion of the Auckland Art Gallery has been unveiled to secure the country's finest collection of art in a fusion of contemporary and heritage architecture.

The redevelopment is the most radical overhaul of the 1887 French-style colonial icon and is set to propel the gallery into the ranks of major international art museums.

The city's other major arts institution, the Auckland Museum, is undergoing its own $60 million overhaul with a striking four-storey suspended bowl and copper dome over the once-vacant rear courtyard.

The goal of the art gallery project is to earthquake-proof and restore the 1887 and 1916 components of the main building while developing a complementary, flexible and contemporary design linking the whole to Albert Park. Features include a series of hovering canopies relating to overhanging pohutukawa trees in Albert Park, stone walls, terraces and open views to the park.

The gallery will be expanded to the north along Kitchener St with an entranceway and atrium with natural light and outdoor views. A second atrium will be built at the south end of the complex to complement the northern atrium and open up the original face of the Wellesley gallery. Between the atriums will be new exhibition spaces, including a sculpture terrace, to expand the existing display area by 50 per cent.

Architect Richard Francis-Jones, of Sydney-based FJMT, said the building would be turned into an exciting, vibrant and welcoming "place of art".

"Ultimately our buildings have to be beautiful and engaging," Mr Francis-Jones said at a breakfast launch of the plans yesterday.

FJMT, with an international reputation for high-profile public buildings, and Auckland's Archimedia, which designed Auckland University's School of Business, were selected from 17 proposals last year to bring the gallery up to international standard.

Gallery director Chris Saines said that when the expansion was complete in mid-2009, the public would experience exhibits in an entirely different way. The gallery will close for up to 27 months from August next year and temporarily relocate across Kitchener St to the New Gallery.

"We want to make the gallery friendlier to families, more relevant to young people and more inviting to the community. With this in mind, we wanted a design that made the gallery feel as transparent and inviting as possible," Mr Saines said.

The Auckland City Council is giving $25 million to the project and the Auckland Art Gallery Foundation has been set up to raise the other $65 million, the largest target for a New Zealand cultural institution. Foundation chairman and Ernst & Young chief executive John Judge is confident of raising $35 million to $40 million from charitable sources, art trusts and patrons before seeking a contribution from the Government.

The Government has given $27.1 million towards the $60 million Auckland museum project.It paid $317 million for the national museum, Te Papa, in Wellington.

Mr Saines travels to the United States today to see if the Getty Foundation will contribute towards the heritage component and to seek donations from people with New Zealand connections.

Auckland City Mayor Dick Hubbard said the gallery project would make a new home of international quality for a collection of national importance.

Museum director and former art gallery director Dr Rodney Wilson said the makeovers of the two institutions would create "absolutely superb buildings".