With its towering kauri ceilings and huge glass panes, the revamped Auckland Art Gallery is becoming a showplace for the construction industry's skills.

Today, a party of 40 chartered surveyors will follow other industry professionals who have brought their hard hats and high-visibility vests to tour the site, though a date for the public opening has not been announced.

Surveyors will learn from Hawkins Construction project manager Grant Thomas about the challenges, complexities and craftsmanship involved since work began on the $121 million job in September 2008.

Highlights are the glass walls of the north-facing atrium, which are the largest panels to be used in the Southern Hemisphere, and an innovative post-tensioned facade system using stainless steel rods.

Exhibition space will increase by 75 per cent, enabling 800 of the gallery's 14,620 art works to be displayed.

Although safety fences surround it, the form of the new gallery structure merging with parts going back to 1887 can be seen from Albert Park and Kitchener St. A gallery spokeswoman said work was progressing well towards an opening this year.

The project was within the $121 million budget and Auckland Council confirmed it would put in $56.1 million and the Ministry for Culture and Heritage $31.5 million. Auckland Art Gallery Foundation is raising $33.4 million.

Art patrons Harriet and Michael Friedlander, Dame Jenny Gibbs and Alan Gibbs, and Julian and Josie Robertson will have galleries named after them.

The complex will have three distinct architectural interiors - the result of restoring and strengthening heritage parts and adding new facilities and a ceremonial entrance under a tree-like canopy.

20,000 cu m of material excavated
5000 cu m of concrete
400 tonnes of structural steel
200cu m of NZ kauri timber
850,000 man hours on site
175 workers a day