A woman and a girl have escaped injury after the car they were travelling in sank into a lake southwest of Brisbane.

Police said the pair was travelling in a small car along Springfield Lakes Boulevard in Springfield Lakes when the vehicle entered the water just before 8.30am on Monday.

It is believed a third person, who was also unharmed, jumped into the lake to try to rescue the pair.

An ambulance spokeswoman said the female driver and the girl were taken to Ipswich Hospital but were uninjured.

The cause of the accident is unknown and police are yet to interview the driver.

The vehicle remains underwater.