Heavy rain is expected to cause ‘significant’ flooding in parts of NSW this week.

The BOM has warned of heavy rain and damaging winds for the Hunter and Mid North Coast from tomorrow, with Sydney also in line for more wet weather.

The NSW State Emergency Service (SES) is said it’s preparing to deal with the impact of up to 180mm in parts north of Newcastle.

There are also warnings of strong winds and hazardous surf in the area, which includes the Hunter region.

The Bureau of Meteorology forecast 24-hour rainfall totals of 50 to 100mm, with possible isolated rainfalls over 180mm in 24 hours.

Strong winds averaging 50 to 60 km/h, with gusts up to around 90 km/h are possible.

Assistant Commissioner Sean Kearns ESM said rivers and creeks are already rising.

“Flood alerts have been issued for areas across the Mid North Coast and Hunter due to the potential flooding. The NSW SES has activated flood rescue units and is equipping local communities for the anticipated extreme weather conditions,” he stated.

“If you do come across a flooded road, stop turn around and find an alternative route.”

Flooding is likely on the Hunter, Williams, Patterson, Myall, Manning, Nambucca, Gloucester, Bellingen and Orara Rivers, the SES said.

Strong winds reaching speeds of 70-80 km/h are probable along the coast on Monday and Tuesday, accompanied by dangerous surf conditions with five-meter waves expected from Sydney to Port Macquarie.

As the wild weather started to hit on Saturday night, the NSW SES responded to 137 calls for help.

Most were in Lake Macquarie and Port Stephens but others came from as far south as Waverley and Woollahra in Sydney’s east.

After a mostly wet week, the rain is set to continue in NSW.

Rainfall totals of 50mm to 100mm are expected.

Sydney can expect more rain to start the week, which will ease off into showers by Wednesday.

Temperatures will peak at a cool 20c.

Melbourne will stay sunny until Wednesday when showers are expected.

Brisbane will also get a wet start to the week, while Adelaide will be mostly sunny.

Hobart is also in line for some sun, which will peek through the clouds as the week goes on.

Perth will be a sunny 25 degrees.