The bodies of a mother, her daughter and a dog have been discovered at a home in southwest Sydney in what police believe was a suicide pact following a family tragedy.

A note was found on the door of the family home in Greenacre saying that the two women would be found in a car in the backyard.

Inside the car, a woman in her 50s and her daughter aged in her 20s were found deceased with a second note, explaining that they could no longer deal with the pain following the death of a 24-year-old man, the son and brother of the women, who passed away after a surgical procedure went wrong.

The two women were found at around lunchtime on Monday. The family dog also died and was found inside the car with them.

It’s understood that a neighbour made the horrific discovery and was treated at the scene for shock.

A report is now being prepared for the coroner.

If you or anyone you know is seeking help you can contact Lifeline on 13 11 14.