The $25 million redevelopment will be staged over 12 years, with trades students helping to construct the buildings to keep down costs.
Initial concept plans show a multistoreyed U-shaped building on the Riego St boundary linking to a multistoreyed rectangular building on the Anzac Ave frontage.
An atrium containing a student common room and upper plaza will link the buildings to two art school buildings which will be retained.
One of the buildings was completed about a decade ago and the other only last year.
A barn for horticultural studies overlooking the Water of Leith is proposed, while the riverside area will be developed into a recreational space.
Chief executive Phil Ker said yesterday the plans were exciting.
"After being focused on the immediate for so long, it is refreshing to be planning further out."
When completed, the buildings would cater for about 900 existing art and engineering students and 70 staff, and for further roll expansion, he said.
The polytechnic council had already approved stage one of the six-stage project, the demolition next month of a building at the northern end of the site, Mr Ker said.
Construction of a $1 million teaching space for bachelor of engineering technology students was scheduled to begin in September.
Last year, the Government withdrew $12.5 million of capital funding earmarked to build the new Otago Institute of Design.
Mr Ker said the Anzac Ave project had deliberately been staged so the polytechnic could carry out the work within an annual capital expenditure budget of about $2.5 million.
"There is no money available from the Tertiary Education Commission for capital projects.
"We know that, so it it a waste of time asking for it."
Chief operating officer Philip Cullen said two main drivers were behind the project - the poor state of repair of the old art school buildings, and the need for the polytechnic to move out of L Block, the engineering department buildings opposite the art school on the east side of Anzac Ave.
While the polytechnic owned L Block, the land was owned by businessman Earl Hagaman.
When the annual ground lease rent was reviewed two years ago, Mr Hagaman's "opening bid" was a 10-fold increase, Mr Cullen said.
Following arbitration, that was decreased to just under a five-fold increase.
With L block only a stone's throw from the Forsyth Barr Stadium, Mr Cullen said it was inevitable land in the area would become more valuable.
"We want to be out of there and into buildings on our own land before the next rent review in 2022."
Polytechnic council members supported the project at a meeting on Thursday.
Chris Staynes said it was "well worth pursuing".
"All the surrounding land near the stadium is going to be worth a lot more in years to come.
"With the development that is already going on in the area, if we don't plan ahead we won't get the facilities we need."
