Wild weather predicted for NSW

Six-metre waves are predicted off parts of the NSW coast, while snow is causing chaos in the Blue Mountains and the closure of Orange Airport.

Large and powerful surf conditions are expected to develop throughout Friday, creating hazardous conditions for coastal activities such as surfing, swimming and rock fishing, according to the Bureau of Meteorology (BoM).

Huge waves are expected off the Illawarra, Batemans and Eden coast, with storm-force winds to whip up heavy surf conditions of up to three metres along the shoreline.

BoM has also issued gale-force wind warnings for Sydney Harbour, Botany Bay and the Coffs, Macquarie and Hunter coasts.

"Right now it's dead flat in Sydney but by tonight fairly wild conditions will develop," BOM forecaster Michael Logan said.

Meanwhile heavy snow in the state's central-west has led to the closure of Orange Airport and caused problems on roads between Bathurst and the Blue Mountains.

Morning flights have been cancelled or delayed at Orange Airport but the airport is expected to reopen in the afternoon.

Emergency services have attended a three-vehicle accident at Katoomba, which has affected traffic on the Great Western Highway on Friday morning.

Roads between Oberon and Goulburn and between Oberon and Bathurst remain closed. Motorists are being urged to use other routes.

Further south, blizzard conditions have been forecast for the Snowy Mountains in areas above 700 metres.