A flood watch notice has been issued for the Werribee River catchment.
Minor flooding is expected across the area from this evening.
A low pressure system will form off the southern NSW coast and is expected to bring rain to the catchment.
From Thursday to Saturday, three-day rainfall totals of 30 to 60 millimetres are forecast.
Monitor weather forecasts and river levels online by visiting www.bom.gov.au/vic/warnings.
Details: www.emergency.vic.gov.au or call the VicEmergency Hotline on 1800 226 226