Sydney,  As record rainfall sweeps across Australia's eastern coast, flash flooding and severe thunderstorms have prompted severe warning after a third loss of life.

In the early hours of Friday morning, police uncovered the body of a man who went missing in his vehicle in floodwaters on the Central Coast to Sydney's north, Xinhua news agency reported.

The incident brings the total death toll from the floods to three, as two more people in the Australian state of Queensland were caught in flood waters earlier in the week.

The Queensland Bureau of Meteorology (BoM) has issued severe weather warnings to the north of state capital Brisbane.

The weather forecasting body flagged "very dangerous, slow-moving thunderstorms" and "intense rainfall that may lead to dangerous and life-threatening flash flooding."

"Avoid drowning. Stay out of rising water, seek refuge in the highest available place. Prevent damage to your vehicle. Move it undercover, away from areas likely to flood," read a warning posted by the BoM.

While the worst of the rain has already passed in the state of New South Wales (NSW), the BoM has forecast rain to continue between 10 and 30 mm into next week.

Over the last week areas of NSW and Queensland have experienced between 100 and 200 mm of daily rainfall, which has seen rivers overflow, metropolitan areas flood and major road blockages.

The record levels of rainfall have in part been linked to a La Nina weather system which peaked last month. It is expected that the extreme wet weather conditions could continue into March.