He said a major consent application has just been lodged for the fixed roof, which will be made of light-transmitting material over both the stands and the pitch.
It is understood the multi-use facility will be just the second fully-roofed stadium in the world to feature a natural grass playing field, after Dunedin's Forsyth Barr Stadium.
Noonan says they're also working with manu whenua to incorporate cultural designs on the external building facades and seating bowl.
And he told city councillors the risk-sharing model, agreed with construction company BESIX Watpac, has worked out well.
"We thought we'd potentially have quite a bit of a dewatering to be done, but wasn't as bad as we thought. Same with contamination, we shared that risk and it's certainly better than we thought. Overall, we're very happy with where the risk is sitting against our projections."
The arena will have a capacity of up to 30,000 for major sports matches, and up to 36,000 for big concerts and events.
- By Geoff Sloan
Public Interest Journalism funded through NZ On Air