Weather in Sydney, Melbourne, Brisbane: When the rainwater stops on the east coast of Australia

Australia's east coast is being deluged with 'intense' rain, with warnings the wet weather will continue for days and the threat of flash flooding looms.

Sydney, the Illawarra and Central Coast regions are forecast to receive up to 80mm of rain on Monday, with heavy falls expected to ease later in the day.

Rain is likely to continue for the rest of the week, with up to 30mm forecast for Tuesday. Warm, drizzly and humid conditions are forecast through Thursday.

Brisbane is expected to see up to 10mm on Monday, while Melbourne will welcome dry conditions for the second full day of the Australian Open.

No rain is forecast for the Victorian capital today, apart from light showers in some north-eastern suburbs and the chance of a thunderstorm. Little rain is expected in Melbourne this week.

The Sydney, Central Coast and Illawarra regions are forecast to experience heavy rainfall on Monday

Weather Zone meteorologist Yoska Hernandez warned residents of Sydney, the Illawarra and Central Cost should exercise caution.

'“60-80mm of rain is expected, falling mainly in the morning and afternoon,” she warned.

'If thunderstorms or particularly heavy showers develop, some coastal areas and adjacent inland areas could potentially receive 80-120mm.'

The strongest part of the wet weather system will shift north later on Monday, changing to lighter showers as the day progresses.

“Meanwhile, the Mid North Coast and Northern Rivers districts are likely to experience the most substantial rainfall in the afternoon and evening,” Ms Hernandez said.

'Other regions along the NSW coast and adjacent inland areas are expected to see falls of 30-60mm on Monday, with isolated heavy rain also possible for parts of the Mid-North Coast, with the potential for rainfall in excess of 100mm. '

Despite showers easing, a further 20 to 40mm of rain is expected to fall along the NSW coast, with the wet weather likely to continue until Friday.

Meanwhile, warmer than normal ocean temperatures have led to record high humidity in Sydney, while sticky conditions were also felt in Brisbane.

It comes as severe weather continues to lash Queensland, with those in the south-eastern parts of the state inundated with rain, along with monsoon-hit residents in the far north.

The worst affected areas remain in the north, with some flood-affected parts set to receive up to 30mm of rain every day this week.

A flood watch remains in force for Cape York Peninsula and parts of the Gulf of Carpentaria, while flood warnings are issued for the Paroo, Tully, Murray, Barcoo, Bulloo and Diamantia rivers.

A major flood warning has been issued for the Paroo River around Eulo as rain causes river levels to rise 'significantly'.

“The Paroo River at Eulo is currently 3.8 meters high and is expected to rise slowly, with moderate flooding (average flood level 3 metres),” the Bureau warned.

Elsewhere, Adelaide will be sunny with a high of 34 degrees on Monday, while Perth will be mostly sunny and will also reach a high of 34 degrees.

A ferry is shown passing through fog under the Sydney Harbor Bridge

A map of areas affected by storms overnight in Queensland is shown

But while WA's capital remains sunny over the next few days, Adelaide is headed for clouds and some rain.

It will be 29 degrees in Darwin on Monday, but it will remain windy and there will be heavy rain showers. The coming days will also bring rain and storms to the NT capital.

Canberra is in for a few wet days, with temperatures ranging from a low of 13 degrees on Tuesday to a high of 27 degrees on Wednesday.

Hobart will be mostly cloudy and wet for the next few days, with the exception of Tuesday, which will be sunny and could reach a high of 29 degrees.