The local Transport for NSW Regional Director Anna Andrews said they were forced to do so after "a number of vehicles ignored the lights and the directions of traffic control".

The New England highway is closed to one lane at Bolivia Hill, with one direction stopped to traffic by traffic lights while waiting for oncoming cars to pass. But not all motorists follow the law.

"These motorists are putting themselves and other road users in danger, as this section of road has no opportunities for vehicles to overtake or pass," she said.

"NSW Police will be providing additional enforcement, and will use the CCTV to identify offenders."

TfNSW said the cameras would also help to reduce what can be a fifteen wait at the pinch point. Works are continue into next year.

The two kilometre upgrade, which will cost the taxpayer $80 million, will help smooth out the notorious black spot halfway between Tenterfield and Glen Innes. For years vehicles including trucks regularly ran off the road down a steep cliff, killing a number of drivers and passengers.

A semi-trailer ran off the hill as late as last October. A pair of cars allegedly stolen cars were stopped at the construction works last month.

Ms Andrews said motorists must obey the traffic lights at all times as there is no ability to see oncoming traffic.

"Motorists are urged to be patient and allow extra travel time, and are reminded the wait for the lights to change is typically no more than 10 minutes," she said.

Transport for NSW also thanked the community and heavy vehicle operators for their patience while this essential work is carried out.