Home sprayed with bullets in Sydney's west

Police are speaking with a couple whose house was sprayed with bullets and car was set alight in western Sydney to work out a motive for the attack.

A 38-year-old man and his wife were inside their home in Bratsell Street, Moorebank, when they heard bangs outside their residence about 1am (AEDT) on Friday.

Shortly after, they saw their Mazda 4WD on fire in their driveway.

Firefighters extinguished the blaze, while police officers found bullet holes in the front of the house.

Fired cartridge cases were also found on the home's lawn.

Neighbours say they heard three to four shots, Macquarie Radio reported.

The couple weren't injured.

Police are urging people with information to call Crime Stoppers on 1800 333 000.