Insurers are monitoring the impact from storms that have brought heavy rainfall and flooding to the Hunter and Mid North Coast regions of NSW. 

The State Emergency Service received more than 1405 calls for assistance in the 24 hours to 5am as weather conditions worsened overnight.

Four evacuation centres were open today and more than 4000 homes had lost power. 

Major flood warnings remain active and the Bureau of Meteorology says further heavy to locally intense rainfall is likely into tomorrow as effects from an offshore weather system continue.

“The soils are completely saturated and any rainfall ... will run off and go straight into the creeks and rivers,” bureau hazards manager Steve Bernasconi said.

The significant weather event, which has also brought damaging wind, has been caused by a trough around the Mid North Coast that is expected to move slowly north, he says. 

The affected area extends from north of Coffs Harbour to Lake Macquarie and inland to the North West Slopes and Plains and Northern Tablelands districts.

Mr Bernasconi says Taree received 190mm of rain in six hours, and Gloucester 61mm in one hour. Rainfall rates have been comparable to significant weather events in 2011 and 2015.

For the 24 hours to 9am, the bureau reported Taree received 279mm and Port Macquarie 239mm.

Major flood warnings have been issued for the Paterson and Williams rivers, while at Gloucester the river is expected to remain above the major flood level this afternoon, with further rises possible overnight. The Manning River at Taree may also exceed the major flood level.

SES northern zone commander Andrew Cribb says rescues have been made, and short, intense bursts of rain could cause further flash flooding. More evacuation centres are expected to open.