The NSW Government's implementation of the cameras, which caught almost 100,000 drivers in a six-month trial earlier this year, has been designed to have an "anywhere, anytime" impact.

The cameras come without warning signs, typically used with red-light and speed cameras, and many will be portable so they can be easily moved and used on almost any road in the state.

Instilling the element of surprise by ditching the warnings signs is part of the government's effort to curtail NSW's staggering road toll, which has reached 330 fatalities already in 2019.

When the legislation to implement the cameras was announced in October, Roads Minister Andrew Constance made no apology about forgoing warning signs.

"I want behaviour to change and I want it changed immediately," he said.

"It's not about revenue raising; it's about saving lives."

The cameras will record the offence of a phone being "held by, or resting on, the driver of a vehicle".

Drivers caught in the first three months will receive a warning letter.

Offences thereafter will result in a penalty of five demerit points and a $344 fine, or $457 in a school zone.

The detection system operates day and night and in all weather conditions, using high-definition cameras to capture images of the front-row cabin space of all vehicles.

The system uses artificial intelligence to automatically review images and detect offending drivers.

It also excludes images of non-offending drivers from further action.

Images that the automated system considers likely to contain a driver illegally using a mobile phone are then verified by a human.