The Baird government will tackle Sydney's housing affordability crisis by shaking up metropolitan planning with an independent Greater Sydney Commission tasked with ensuring 664,000 new homes are built by 2031.

The NSW budget will contain funding to establish the London-style commission, a year after it was announced by Premier Mike Baird, The Sun-Herald has learnt. An international search will be held for its chief.

Premier Mike Baird says releasing greenfields sites for new housing and funding infrastructure will ease property price pressures. Credit:Fiona-Lee Quimby

The high-powered commission is expected to include six local government representatives, the heads of planning, roads and transport agencies and three independent members. It will cut through arguments with individual councils over hot issues such as high-rise apartments and transport.

As the housing affordability debate rages, the Baird government has insisted that increasing housing supply and supporting new housing estates by funding infrastructure is the best way to put downward pressure on prices.