A bus driver has been charged with exceeding the speed limit by more than 20km/h with 48 passengers on board near Mittagong on Sunday.
Police from Goulburn Highway Patrol stopped the 55-year-old driver while he was heading north on the Hume Highway about 4.20pm.
The man was allegedly detected travelling at 121km/h, in a 100km/h signposted zone.
Most of the passengers were tourists, police said.
The driver was issued with a range of infringement notices for speeding and work diary offences.
Police are also investigating whether there was a possible speed limiter defect.
Highway patrol police continue to be deployed in large numbers across the state as part of Operation Saturation - a joint initiative between NSW Police and the Centre for Road Safety, which runs until March 23.
Commander of the Traffic and Highway Patrol Command, Assistant Commissioner John Hartley, said those who continued to risk lives on the road would be caught during the operation.
"The Joint Heavy Vehicle Taskforce will now examine the operations of the bus company involved in this incident to ensure safety compliance across their fleet," he said.
"Our main focus is to further reduce the road toll."
Highway patrol and general duties officers will be targeting speeding, drink-driving, seat belt and mobile phone compliance for extended shifts during the operation.