Wet and warm weather has hampered hazard reduction burns in Greater Sydney ahead of the official start of the fire season next week.

The NSW Rural Fire Service and National Parks and Wildlife Service have been trying to take advantage of relatively cool and dry conditions.

But a storm late on Monday and expected hot weather on the weekend forced the postponement of a pair of major planned blazes this week.

Among the postponed burns were a planned reduction burn of 230 hectares in Ku-ring-gai Chase National Park in Sydney's north and a 476-hectare burn in the Royal National Park.

On the other hand, a 410-hectare burn in the Hawkesbury near Blaxland Ridge went ahead on Wednesday.

NSW RFS Superintendent Ben Shepherd told 702 ABC Radio Sydney that for the past 4 years it had been hard to

See Full Page