The reserve was among a number council had earmarked for sale, using the income to help lower its burgeoning debt.
Councillor Sue Westwood, a long-time advocate for retaining the reserve, said discussions about its future had been going on since 1981.
"This is not a council asset but rather a community one, and as councillors it's our job to be stewards of those assets," Mrs Westwood said.
Claims about financial benefits accruing from any subdivision were minimal in terms of the council's overall debt.
"To say it will have a significant impact on our debt is simply ridiculous."
She said council was flawed in its thinking if it sells off reserves because "once it goes, it's gone".
Councillor Hamish McDouall said while he was not opposed to asset sales, it was matter of finding a balance between amenity value and yield. For that reason he was not opposed to selling the bottom part of the reserve.
It was this compromise which council eventually settled on.
"The viewshaft is an extraordinary one and among one of the best in the country. A properly tended reserve would be something that everyone could enjoy," Cr McDouall said.
Councillor Helen Craig favoured retaining the top part - and most visible part of the green space - as reserve, saying selling it would be "a mistake".
Councillor Rob Vinsen, who has been a staunch advocate of the subdivision, said debt reduction was a rallying cry during the local body elections and this sale gave council that chance.
"Council needs to cash in on its surpluses. There's a lot of reserve spaces nearby at Otamatea Reserve and the land across the road from this reserve," Cr Vinsen said.
"This discussion is perpetuating talks that started in the 1980s. Increasing pressure of debt means we must take every opportunity that presents itself.
"We've seen resolutions made but never actioned and procrastination makes this council look bad," he said.
He got support from Councillor Philippa Baker-Hogan, who said it was one of the hard decisions council had to make.
The vote signed off the subdivision of the lower portion of the reserve, along with necessary building covenants restricting building height, while retaining the unblemished reserve for the public.
Mayor Annette Main said the decision was a signal to the community the council was prepared to listen to people's views.