Two men have been shot in Bankstown in Sydney's southwest, with police later arresting three men over the attack.

Residents on West Terrace reported hearing gunshots soon after midnight on Thursday, before two men arrived at Bankstown Hospital suffering gunshot wounds.

Their injuries are not believed to be life-threatening, police say.

Shortly after 1am (AEDT), three men were arrested in Parramatta and taken to Merrylands Police Station.

A crime scene has been established in the hospital car park, where the men's vehicle was found containing with several bullet holes.

A crime scene has also been established in West Terrace, where a number of items have been seized for forensic examination.

Detectives are waiting to speak with the injured men.

Police later said were investigating a separate shooting at a house at Bringelly, in Sydney's southwest.

Officers were called to Mandina Place about 1am after residents reported hearing gunshots.

A number of shots had struck the front of the single-level brick house, which was empty at the time.