All four vehicles involved in the collision were travelling north near the Mooney Mooney Bridge.
Earlier, emergency services had to be called to rescue motorists trapped in their cars in Sydney’s inner suburbs after heavy downpours and flash-flooding.
Suburbs near Sydney Airport, including Zetland, Alexandria and Waterloo have been worst affected by flash-flooding after drizzle turned into torrential rain this afternoon.
Phil Campbell, spokesman for the State Emergency Service, said his organisation, along with police and fire services, had already performed five rescues from cars that had become trapped in rising floodwaters on Sydney roads and urged commuters travelling home to exercise caution.
The people of New Zealand would like to thank Australia for taking our crap weather during the month of May. Most parts of New Zealand have been experiencing well above average temperatures while over in Aussie it has been colder and wetter than normal.