NSW Police issued 174 fines to drivers on Wednesday for not keeping left on the state's busiest roadways, including the M4, M5 and M7 in Sydney.

It was one of the first times police have specifically targeted motorists for the offence in a long time.

And they have indicated they will do it again to ensure Sydney's increasingly congested motorways are not made worse by long lines of vehicles queuing up behind motorists who fail to keep left.

The lane hoggers were nabbed on Wednesday during Operation Compliance 2, which also targeted drivers using their mobile phones or failing to wear seat belts.

Drivers must keep left on multi-lane roads that have speed limits of more than 80km/h, while disobeying a "keep left unless overtaking" sign on any road is also an offence. They offences carry fines of $108 and two demerit points.

Assistant Commissioner John Hartley said lane hogging was one of the offences that people most complained about and it featured regularly in surveys and on talkback radio as the pet hate of most motorists.

"Those not keeping left, despite significant signage on our highways, continue to impede the free flow of traffic and present significant risks to emergency services who need the right lane to get help to those that need it quickly," he said.

Mr Hartley, of the state's Traffic and Highway Patrol Command, said drivers who hugged the inner lanes often created long queues of vehicles behind them and caused other motorists to take risks so that they could pass.

"These people are holding up a whole line of traffic. People sticking in the right-hand lane is one of the key frustrations of other motorists," he said.

Mr Hartley said the lane hoggers did not fit a stereotype as they tended to be drivers of all ages and gender.

But he emphasised there was no excuse for motorists who failed to keep left because the driving code made clear that it was an offence.

The state's road toll of 216 is 45 higher than the same time last year, which has been partly blamed on people failing to wear seatbelts.

Police fined 324 motorists for not wearing seat belts on Wednesday, and 940 for using a mobile phone while driving.

The fine for not wearing a seatbelt is $325 and three demerit points. Using a mobile phone while driving incurs the same financial penalty but with four demerit points.