NSW drivers who threaten lives by using mobile phones behind the wheel risk being caught by unmarked cameras as new technology rolls out across the state.

However, drivers captured flouting the law will initially be spared punishment during a three-month grace period which will see them receive a warning letter only.

Transport Minister Andrew Constance says the world-first technology targeting phone use via fixed and mobile trailer-mounted cameras would roll out from Sunday, December 1.

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It follows a six-month trial which caught more than 100,000 drivers.

“It’s stupid, it’s dangerous, it’ll kill someone - and people are not getting the message,” Mr Constance told reporters on Friday, November 29.

“Driving with a mobile phone is like driving drunk. Driving with a mobile phone is equivalent to .08 behind the wheel of a car and that’s why we’re now being hard and fast on this.”

Chevron Right Icon “Driving with a mobile phone is like driving drunk.”

Mr Constance said the grace period was fair and the state government was “being kind in that regard”.

“We want people to get the warning letter and change their behaviour immediately, which I believe will happen,” he said.

Police will still enforce illegal phone use and issue infringements as usual during the grace period.

About 45 cameras will ultimately be rolled out across Sydney and regional NSW on December 1. They won’t be marked by signage.

What’s the penalty?

At the conclusion of the warning period, drivers will be fined $344 - or $457 if caught in a school zone - and lose five demerit points.

Drivers can legally use phone cradles and make and receive phone calls through Bluetooth, Mr Constance said.

He said images would be destroyed within an hour of them being taken if phones weren’t detected via an algorithm.

If mobiles were present, the images would then be considered by two qualified professionals.

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Regional Roads Minister Paul Toole says an estimated 135 million vehicle checks will be performed annually under the program by 2023.

NSW Centre for Road Safety executive director Bernard Carlon says modelling shows the cameras could prevent 100 fatal and serious injury crashes over five years.