A flood warning has been issued for Bulga on Saturday, with minor flooding already occurring and moderate levels possible.
The Bureau of Meteorology said heavy rainfall on Wednesday and Thursday had caused river level rises along the Wollombi Brook and its upper tributaries.
Minor flooding is occurring at Bulga and further rises to the moderate flood level are possible overnight Saturday into Sunday.
The river level may reach the moderate flood level (3.70 metres) overnight.
There is only a slight chance of a shower in the Hunter on Sunday before sunny skies predicted to return on Monday.