Te Kakano, which would be 5m high, was included in the project proposal assessed by consultants Deloitte, which proceeded the June public referendum on the building. However, it was not mentioned in the referendum documents.
Whangarei Art Museum Trust chairman Grant Faber offered to cover the costs of maintaining the building if desired by council, though staff advised it would be the first time such an arrangement had taken place.
"Inspired by many Hundertwasser elements the sculpture rises from the earth in a spiralling koru and integrates elements of earth and colour," Mr Faber wrote in his pitch to the council.
"It is designed to blend with the surrounding green space. The garden rooftop lookout from the sculpture provides a striking vantage point to view the town basin."
Mr Faber said if the Hundertwasser project failed, Te Kakano would stand alone as an "iconic artwork".
The Hundertwasser's project action group, replete with 50 volunteers, reported almost 38 per cent of the $16.25 million required for the project to go ahead had been raised. The whole amount needs to be available by June 2017 for the centre to go ahead.