Police pursuit ends with car in NSW pool

A police pursuit has ended with officers rescuing a woman and her six-year-old daughter from their car after it plunged into a backyard swimming pool in Sydney's far west.

NSW Police say they pursued the 37-year-old woman's Hyundai though Penrith and St Marys on Monday afternoon before the chase was called off.

Later, an unmarked police car again tried to stop the Hyundai, which was allegedly being driven erratically with the girl in the passenger seat.

A further attempt to pull the car over failed before the 37-year-old driver reversed through a fence and into a backyard swimming pool in Hobartville.

"The engine was still running as police jumped into the pool and rescued the six-year-old girl and her 37-year-old mother," a police spokesperson said in a statement.

The woman was taken to Nepean Hospital. The child is being cared for by her father.