The Lotteries grant punches the project past the $16.25m bottom line drawn by Whangarei District Council (WDC) after its controversial referendum of 2015.
That amount had to be in hand by June 30 or all bets were off. Only two weeks out the project was still $1.25m short of the line.
The grant has been hailed as a win "for and by Northland" by Hundertwasser Arts Centre (HAC) project director Andrew Garratt.
"The incredible effort from this community to raise funds and voice to this project has been heard and we are delighted to have met one of the key requirements of the referendum," Mr Garratt said.
Whangarei Mayor Sheryl Mai, an ardent supporter of HAC, said the grant "was wonderful, heartening news", although the entire funding has not yet been raised.
"This project has withstood passionate arguments for and against it.
"After a decade on tenterhooks it will be an emotional moment for many to realise that now they have categorically met the conditions of the agreement made with [the] council after the referendum," Ms Mai said.
"Thank you everyone who has taken part in this project, on both sides of the debate.
"I rejoice for all who have backed the project through gestures and donations, large and small."
Mr Garratt also praised the public for its generosity throughout the process, and its response in the last couple of weeks as the "raise it or lose it" call went out.
"We are so very appreciative of this grant from Lotteries, as well as the amazing response from the community in the last few weeks, with thousands of dollars raised through donations, art sales and pledges."
It is estimated the Hundertwasser Art Centre will attract more than 150,000 paying visitors a year. Latest studies from Northland Inc estimate that the HAC will have an economic impact of $26m a year for the region.
