The youth worker had just finished night shift and was confronted with metal and flashing lights, seemingly flying towards his windshield from the other side of the highway.

A truck heading northbound near Haywards Bay Drive had lost control in wet weather and mounted the concrete barrier in the middle of the road.

"It was just before the turn off at Hungry Jacks, it was still a bit dark outside, and I've seen these lights and a truck coming over the barrier," Mr Borg said.

"I just swerved from the right lane into the left, the front of the truck came apart and hit my my car as well."

Mr Borg said it was "pretty full-on" but counted his lucky stars the barrier stopped the vehicle from lunging further.

He said the driver of the truck was uninjured but appeared shaken by the incident.

Several people stopped to help direct traffic in the 80km/h zone as dark clouds and rain made visibility of the wedged truck difficult.

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Mr Borg's new Nissan Xtrail has suffered extensive panel damage caused by debris from the truck. 

He described the accident as "devastating" as he only had 1000km on the speedometer.

A spokesman for NSW Police said no-one was injured in the accident though it was blocking two lanes - one northbound and southbound.

Traffic was affected for more than two hours as emergency services had to call in a crane to remove the truck.

Severe weather began on Thursday with torrential rain drowning parts of the Illawarra at times.

State Emergency Services co-ordinator duty operations Neil Wiblin said statewide they had received 950 calls for help since 1pm on Thursday - 106 in the Illawarra/South Coast.

"Across the state we have had three flood rescues and all involved vehicles driving through flood waters, please don't drive through flood waters," he said.

"If it's flooded forget it ... because you don't know wat's underneath the water."

Since 6pm Friday there had been eight call-outs, mainly in the Albion Park area.

The Bureau of Meteorology has forecast thunderstorms through until Monday, with showers likely on Tuesday.