THE NSW Government believes almost the entire state driving population will be surveyed through its new program using special detection cameras to catch drivers with phones at the wheel.

Trialed for the past three months, the government's mobile phone detection camera program has now started slapping irresponsible drivers with a $344 fine and a five demerit-point penalty.

The program, which would be expanded over three years, aimed to scan over 135 million vehicles each year, on metropolitan and regional roads, using 45 fixed and transportable cameras across the state.

Minister for Regional Roads Paul Toole elaborated on how people in remote areas might be caught.

"The cameras are both fixed and transportable, with the trailer-mounted cameras to be frequently moved around the state, targeting illegal mobile phone use anywhere, anytime," Mr Toole said.

Cameras detect phones using an algorithm, then send images to two people who determine whether there is proof to issue an infringement.

Unlike speed cameras, the fixed and trailer-mounted cameras would not be signposted.

A government website stated the program aimed to "reach close to 100 percent of the NSW driving population" by 2023.

Mr Toole said taking eyes off the road for longer than two seconds doubled the risk of a crash.

"Research has found illegally using a mobile phone while driving is associated with at least a four-fold increase in the risk of having a crash in which someone is killed or seriously injured," he said.

"Texting while driving increases the crash risk even further."

The program was a key initiative for the government to achieve its target of reducing road fatalities and serious injuries by 30 per cent by 2021, and to zero by 2056.

During the three-month trial period, nine million vehicles had been checked by the cameras and more than 30,000 warning letters issued to offending drivers.