The New South Wales Government has unveiled an ambitious plan to supply more than 170,000 new homes across greater Sydney.

Eight existing suburbs will be re-zoned to accommodate 30,000 new homes in high density apartment blocks.

The Government has also released greenfield sites on the city's north-west and south-west outskirts to build new houses, business parks and town centres over the next 20 years.

Dubbed "Super Saturday", the announcement on Saturday is one of the state's largest ever housing programs.

Premier Barry O'Farrell says the plan will meet the city's future housing needs.

"It's about ensuring that areas open up as the infrastructure is available," he said. "It's about better balancing the needs of this city.

"Ultimately economics drives everything.

"Our argument is the more blocks of land we can release the greater downward pressure we can put on housing.

"It has been so high for so long because under the former government not enough housing was developed because not enough land was being released."

Speaking at one of the proposed sites, planning minister Brad Hazzard said the plan would solve the city's housing shortage and curb rising prices.

"Box Hill is the jewel in the crown of what we are doing right across Sydney," he said.

"Where we are standing there will be 10,000 homes, there will be 16,000 jobs."

The roads and transport to support the plan will be funded from the Government's $62 billion infrastructure fund.