THE rate of development in established areas of Sydney would be cut in favour of development at the city fringe under a Coalition government, in a retreat from more than a decade of planning policy that has focused on increasing density to address population growth.

Under questioning in Penrith yesterday during a leaders' forum on the future of western Sydney, the Opposition Leader, Barry O'Farrell, said if he won next month's election he would alter the development mix in the government's metropolitan plan.

Going up ... Andrew Nianios on the roof of a home in Oran Park Town. Barry O'Farrell has indicated growth will shift to western Sydney under the Coalition's urban plan. Credit:Kate Geraghty

The strategy, released in December, includes 770,000 extra homes in Sydney by 2036. It says at least 70 per cent of new housing should be in established urban areas, and the rest at the fringe.

But Mr O'Farrell said 70 per cent of development ''should not be through high rise and medium density''.