The Bureau of Meteorology has issued severe weather warnings for parts of NSW, QLD, Victoria, the ACT and Tasmania this week.

Northern Australia is also likely to face a drenching this wet season, after the Bureau of Meteorology predicted above-average rainfall between October and December.

NSW

Western NSW will likely face heavy rainfall and severe thunderstorms on Wednesday, and the Bureau of Meteorology has issued renewed flood warnings for parts of the state.

The deluge of rain this week is likely to cause water rises in already-flooded inland rivers.

A Weatherzone spokesperson said NSW will be the hardest hit state by thunderstorms this week as a strong trough and low pressure system moves across the state.

Central western NSW could expect a 24-hour rainfall total between 50 and 80mLs, the spokesperson said.

QLD

South-west Queensland is set to face heavy rain and storms, and some rivers in the region are at risk of flooding.

"Today, our big concerns are in QLD, NSW and Victoria, because this trough is now in western NSW," a Weatherzone spokesperson said.

The Bureau of Meteorology issued a Minor Flood Warning for QLD's Bokhara River and an Initial Minor Flood Warning for the Macintyre River.

Victoria

Parts of Victoria could face heavy rainfall on Wednesday after the Bureau of Meteorology issued a severe weather warning for Mallee and Northern Country Forecast Districts.

The state could also face high winds, a Weatherzone spokesperson said, with chances of wind speeds of up to 85km possible over Victoria and NSW.

BOM flood warnings have been issued for several rivers in the state, including the Kiewa River, the Loddon River and the Snowy River.

In other news:

On Thursday, the heaviest rainfall will be around NSW, Victoria and northern Tasmania, Bureau of Meteorology said.

Australians are unlikely to get a reprieve from wet weather until Monday, a Weatherzone spokesperson said.