The high school, which has been mired in parent discontent this year, has attracted redevelopment funding of $33.5million.
The new Government funding is in addition to $13million already approved.
Departing principal Wayne Bosley said the school was "absolutely delighted" with the funding announced by Education Minister Chris Hipkins yesterday.
"As a college we are thrilled.
"We have been working closely with the Ministry of Education to come up with a sustainable long-term plan to meet the needs of our rapidly growing community and it is wonderful to receive such positive validation," he said.
Board of trustees chairman Ed Nepia said the school roll was just short of 1200 and the redevelopment would allow it to continue growing to 1600.
The funding would mean both stage 1 and 2 of the school’s master plan would be completed in tandem, over the next three years, he said.
The project will include a whare, two multi-storey classroom blocks and an administration building.
The whare would be the cultural heart of the campus, Mr Nepia said, and would be attached to the administration block.
He described the redevelopment as a "very significant milestone" for the school and the community.
Tenders will be advertised this month and construction is scheduled to begin towards the end of the year.
Mr Bosley, who was being farewelled yesterday, said the redevelopment had been a "very personal project" into which he had invested significant time.
"So I am thrilled to have it finally come into fruition."
Also part of yesterday’s announcement was a $21million rebuild of the Twizel Area School, replacing relocatable classrooms which were up to 49 years old and in poor condition.
Acting Twizel principal Neil Potter said the news was "greeted by students, staff and parents with a resounding cheer".
"Although details are sketchy and expected figures have not been finalised, the decision for a new build will be a boost for the Twizel and Mackenzie community."
