The State Emergency Service has issued a flood watch for several rivers in the Hunter Valley with more heavy rain expected in the next 24 hours.
The Hunter River peaked yesterday afternoon at Maitland at the minor flood level of six metres, with several low-lying roads and bridges cut off.
SES deputy region controller, Ken Speer, says because the catchments are already soaked, any further rain will lead to instant rises in river levels.
"There's a further flood watch that has been issued for the Hunter River and the Paterson and Williams Rivers, that's for tonight and Saturday," he said.
"The Bureau is expecting further rain later this afternoon and tonight and so there is the potential for flooding to occur again in the Hunter River and the Williams and Paterson Rivers.
"Because all the catchments are already all wet any rain will go into the river systems and that's going to cause rises in the rivers immediately," Mr Speer said.
"As we saw last weekend and Monday the rain took quite an amount of time before there was any rise but this time there will be instant rises because of that rain."
© ABC 2013
08:35 EDT The weather bureau has warned more severe weather could hit the New South Wales mid north coast today after heavy rain caused flash floods on Monday.