New South Wales and Queensland in Australia are being threatened by severe weather as more heavy rainfall is forecast, increasing the risk of flash flooding. (Photos: CFP)

According to the Bureau of Meteorology (BoM), Australia heavy rainfall and life-threatening flooding are possible in southeast Queensland and northeast New South Wales.

The Fire and Emergency Department of Queensland said on Sunday it was monitoring the weather and was ready to respond. The department warned that floodwater can rise in minutes and conditions may become life-threatening.

The BoM, New South Wales has updated several severe weather warnings for heavy rainfall and flash flooding. The affected areas include parts of Sydney.

"We need people to be mindful of their flood risks and be prepared," New South Wales State Emergency Service Assistant Commissioner, Nicole Hogan said.