Sydney could see 30mm of rain over the weekend, having an impact on the City2Surf race on Sunday.
The rain is expected to be less intense than last weekend, when over 100mm of rain fell on parts of the state’s Hunter Valley.
Parts of Queensland are also set to be hit by heavy rainfall, with the area between Hervey Bay and Rockhampton in the firing line for massive falls.
The weather conditions are being caused by a northwest cloudband, where warm and humid tropical air from the Indian Ocean passes over Australia.
It is combining with moisture from the Coral Sea, resulting in parts of the east coast being forced to brace for more wet weather.
The extended cloud coverage over large parts of the country will also cause cooler temperatures away from the coast.
Victoria looks set to be spared from much of the rain, with significant rainfall not expected to reach Melbourne until next Tuesday.