New dust storm hits Sydney

A SECOND dust storm to hit Sydney is likely to clear by mid-morning, after every asthmatic in NSW was warned to stay inside today

Ferries going nowhere ... Manly is covered by a red thick dust today with Sydney Ferries cancelled.

A SECOND dust storm covering eastern NSW and Sydney is likely to clear by mid-morning, after every asthmatic in NSW was warned to stay inside today

The Bureau of Meteorology (BoM) has issued a severe weather warning for damaging winds over the ACT and parts of NSW on Saturday.

A cold front is moving from the southeast across the rest of the state on Saturday, bringing raised dust with it.

BoM regional director Barry Hanstrum said the first morning satellite picture showed a band of dust stretching from southeast NSW to the northern parts of the state, covering the Sydney area.

The dust storm hit central western NSW, including Bathurst and Orange, in the early morning and had started to clear by about 7.30am (AEST).

"We've got an area of widespread dust but not as thick as it was on Wednesday, which is likely to clear through the metropolitan area through mid-morning," Mr Hanstrum told AAP.

He said visibility in Sydney was at 5,000 metres, compared to 500 metres on Wednesday, when thick red dust blanketed the city.

The Department of Environment, Climate Change and Water predicts Saturday's air quality to be fair, while health authorities advised people to avoid spending too much time outdoors.

Flights at Sydney Airport have not been affected by the dust storm.