Firefighters battle factory fire in Sydney's west

A Sydney factory has caught fire in Lidcombe, in the city's west, sending large plumes of potentially hazardous smoke into the air.

Live footage captured by traffic helicopters shows smoke extending for some distance.

Superintendent Brendan Hurley told 9News the smoke does not currently pose a threat to the public due to light winds.

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"It's blowing straight up," he said.

Should the wind shift the smoke, residents in surrounding areas will be notified, he said.

Fire crews were notified of the blaze around 7am.

On arrival crews found the factory unit "well alight".

The blaze has now been brought under control.

There are 12 firetrucks currently on scene.

Fire and Rescue will launch an investigation into the cause of the fire, which is not currently known.