Life-threatening’ Floods Force Evacuations In Sydney, Australia (Photos,Video)

Millions of residents have been told to stay home and put their travel plans on hold as 'life-threatening' storms batter NSW.

More than 500,000 people were urged to evacuate flood-prone areas before they became trapped by rapidly rising floodwater.

Camden, Woronora, Chipping Norton, Georges Hill, Lansvale, Moorebank, and Warwick Farm residents were told to leave immediately.

'If you remain in the area you may be trapped without power, water and other essential services and it may be too dangerous to rescue you,' the SES warned.

Evacuation orders were later issued for parts of North Richmond East, Ebenezer, Sackville North, and Leets Vale on the southern side of the Hawkesbury River.

East Hills, Picnic Point, Penrith, Emu Plains, Mulgoa, Jamisontown, North Richmond, Pitt Town, Cornwallis and Cattai have been sent evacuation warnings.

More than three times the average July rainfall has so far fallen in some parts of NSW this weekend, while emergency services received more than 1,400 calls for help and rescued 29 people from flash flooding over the past 24 hours.

Defence force helicopters are on standby to help with rescue efforts if residents become trapped with no way to escape.

Emergency Services and Resilience and Flood Recovery Minister Steph Cooke said the flooding was 'a life-threatening emergency situation' and told residents to postpone travels along the central and south coast of NSW.

'To all communities between Newcastle and Batemans Bay, I am respectfully asking that you reconsider your travel plans at this time,' she said.

'Please stay home if you can. It is really not the time to travel if you are in those areas that are impacted.

'While I absolutely accept that it couldn't come at a worse time for a lot of people and a lot of families, at the end of the day we want everyone to be safe and if that means that you need to reconsider where you go for your holiday, perhaps postpone it or delay just even by a few days.'