The sculpture will sit on a 1.8m-tall plinth scripted with the narrative of the story of Ngatoroirangi, visible from the underpass, being incorporated into the roundabout design.
NZTA will stump up $200,000, the council $150,000 and Te Puia $50,000, leaving another $100,000 to be sought from various community and arts trusts, or private individuals who would like to contribute.
The council's strategy and partnerships group manager Jean-Paul Gaston said the council was still in discussions with the preferred contractor and won't be announcing who it is until the contract had been officially awarded.
"However, we're pleased with how the discussions are progressing...there's been no change to the budget for this project.
"We would like the sculpture to go up at the same time as the roundabout work is finished although we don't yet know if that will happen - the timeline is yet to be finalised," Mr Gaston said.