Police have completed examinations at the scene of a serious single car crash on Illawarra Road at Longford which occurred around 4.45am this morning.

As a result of the crash four people were transported to hospital for medical treatment:

• A 32-year-old woman from Summerhill in a critical condition

• A 29-year-old woman and a 31-year-old woman, both from Longford in serious conditions

• A 53-year-old male from Trevallyn with non-life threatening injuries

The police investigation is ongoing to determine the cause of the crash.