Localised flooding wreaked havoc on Hunter roads with numerous accidents including one car that flipped onto its roof about 8.45am on Industrial Drive at Mayfield.

Floodwaters entered several properties including a retirement village and events across the city were cancelled, including some activities at the Newcastle Show.

A senior forecaster with the NSW Bureau of Meteorology said the rain was unusually localised, with the southwestern corner of Lake Macquarie coppeing such a deluge in such a small space of time with comparatively much smaller falls either side in in Newcastle and Gosford.

A total of 233mm fell in the 24 hours to 9am on Friday in Cooranbong, smashing the previous record of 221mm set on April 16, 1927.

The heaviest rain bucketed down at a similar pace to that set during the Pasha Bulker storm of 2007.

There was 161mm between 1am and 7am at Cooranbong, while bureau figures from the Pasha Bulker storm on June 8, 2007, show Newcastle received 164.6mm in six hours.

Dora Creek was the hardest hit, with 261mm in the 24 hours to 9am, but the weather station there has not been established long enough to set any records.

Blacksmiths and Swansea which copped 231mm of rain, with residents reporting the highest water levels in more than 60 years.

Standing ankle deep in water in her backyard, Jan O’Loughlin, of Blacksmiths, said there had been more water through her propery overnight and Friday morning than during the Pasha Bulker storm.

Miss O’Loughlin, who has lived at her house in Park Parade, Blacksmiths, for 64 years, estimated that the water reached about six inches (15cm).

‘‘We’re a bit underwater,’’ Miss O’Loughlin said.

‘‘It hasn’t stopped raining all night, I got out of bed at six o’clock because I felt sure it would have been flooded because the council doesn’t keep the drains clear so it just floods everywhere down the back lane, Kembrey Lane.

‘‘Our sewer isn’t working properly  so I am too scared to push the button in case it all flows out over the top. This is the third time this has happened, and this is the worst. We had it with the Pasha Bulka and years and years ago but it’s never been this bad.’’

Not far away in Swansea, the residents of Belmont Street were similarly wet underfoot, with water flooding through a laundry, garages and parked cars overnight.

Barry Ham said he couldn’t see the road when he got up on Friday morning, while standing on the driveway.

‘‘My young bloke had his car parked out the front and he had to put into hard out of the way, its flooded through,’’ he said.

Mr Ham said the resurfacing of nearby Pelican Street 12 months had created some serious drainage issues with a pool of water about 150mm deep still in the middle of the road by 10.30am.

‘‘It must be 300mm to 40mm at the outside edges and that’s receded,’’ he said.

‘‘It’s disgraceful.’’

His neighbour Tony Buckley said local flooding had not be as severe for 25 years when a combination of a king tide and heavy rainfall led to flood levels which forced the road’s closure.

Newcastle Courthouse was closed for the day after problems with its fire detection system, and is expected to remain closed on Monday.

NSW Fire and Rescue received a number of calls to the Church Street building on Friday morning after what are believed to be malfunctions caused by significant rainfall and leaks at the century-old building.

Both the district court and the local courts were due to sit, however parties have been told to head home for the day while the problem is resolved.

Calls to the Hunter Business Chamber’s offices in Mayfield are also diverting to the NSW Business Chamber in Sydney due to access issues as a result of high water levels.

Roads and Maritime Services warned drivers away from flash flooding at Kotara, and along Industrial Drive near Elizabeth Street, with further reports of flooding in parts of Mayfield, Islington and New Lambton. 

The Newcastle Night Markets scheduled for Friday night in Newcastle were cancelled, and a warning issued for the Hunter to expect more heavy rain and thunderstorms on Saturday, easing on Sunday.

"A slow moving trough near the Central Coast has resulted in heavy rain over the Central Coast early this morning," the Bureau said.

"As this trough moves slowly northwards this morning, localised heavy rain is expected to extend northwards along the coast."

The State Emergency Service warns people in flooding areas:

- Don’t drive, ride or walk through flood water.

- Keep clear of creeks and storm drains.

- If you are trapped by flash flooding, seek refuge in the highest available place and ring 000 if you need rescue.

For emergency help in floods and storms, ring your local SES Unit on 132 500.