But the Centre for Road Safety said the cameras aren't there to raise money.

There are 16 speed cameras and red-light speed cameras in the Illawarra and, in the 2019-20 financial year, they brought in $4.2 million in revenue.

READ MORE: TIGS camera catches out motorists during COVID lockdown

That's $1.3 million down on the previous figure of $5.5 million.

The Illawarra figures go against the statewide trend, which saw fine revenue remain stable.

Of the Illawarra's $1.3 million shortfall, just over $600,000 can be attributed to a single camera - the one monitoring northbound motorists on the Princes Motorway at Gywnneville.

Traditionally the most lucrative camera in the Illawarra, it fell from $1.8 million to $1.2 million and caught almost 3000 fewer speeding motorists.

The months from March - when the COVID restrictions began - show a noticeable drop in fines in the Illawarra as fewer people were travelling on the road.

Transport for NSW's Deputy Secretary for Safety, Environment and Regulation Tara McCarthy said the effectiveness of speed cameras wasn't gauged on revenue.

"The ultimate goal of NSW's speed camera program is not to raise revenue but rather to improve road safety through a reduction in speeding," Ms McCarthy said.

"A drop in motorists being caught speeding at locations where cameras are installed is pleasing. We want everyone to slow down and drive safely whenever they get in their vehicle."

With speed camera revenue going towards road safety initiatives, there was the chance they would suffer from a fall in speeding drivers being fined but Ms McCarthy said there were other avenues for funds.

"The NSW government also makes significant additional contributions into the fund to ensure that it can continue to fund those programs," she said.