Threatening Sydney grassfire extinguished

A grassfire that threatened a rehabilitation centre and a car yard in Sydney's southwest has been extinguished.

Thirty people were evacuated from Odyssey House when the blaze broke out in a surrounding paddock near Stennett Road, Ingleburn at 3pm on Sunday, Fire and Rescue NSW spokesman Adam Dewberry said.

Strong winds pushed the fire towards hundreds of new cars at a nearby car yard.

Seventy hectares were burnt before firefighters contained and extinguished the fire.

"It's a reminder that bushfire season is approaching and everyone needs to be vigilant," Mr Dewberry said.

The cause of the fire is not known at this stage, he said.