The Bureau of Meteorology has issued a flood watch for the Queanbeyan and Molonglo rivers on Thursday and Friday.
There is a greater than 70 per cent chance of minor flooding and flash flooding in this region from late Thursday.
Severe Weather Warnings will be issued as the cold front and rain band move through NSW.
A BOM spokesperson urged people living or working along rivers and creeks to monitor weather forecasts and prepare to move to higher ground if needed.
"Flood Warnings will be issued if Minor Flood Level is expected to be exceeded at key sites along the main rivers for which the Bureau of Meteorology provides a flood warning service," they said.
"Across NSW over 70 per cent of Flood Watches are followed by flooding within the catchment."
For emergency assistance call the SES on 132 500, and call 000 immediately for life threatening emergencies.
For the latest weather forecasts, rainfall and rain level information, see bom.gov.au.