Riverina Highway Patrol Acting Inspector Ben Smith said there were "a couple of disappointing incidents", including 26 drivers testing positive for either drugs or alcohol in their system out of a total 1801 RBTs conducted.

Acting Inspector Smith said speeding was also an issue, with two incidents of particular concern.

"We had a 27-year-old male from Wellington detected travelling at 163km/h along Goldfields Way, Junee, on Sunday, with police also alleging he was using his mobile phone while speeding," he said.

A second incident involved a P1 provisional licence holder allegedly caught travelling at 142km/h along the Sturt Highway at Galore.

"That 22-year-old male from Narrandera also tested positive for methamphetamine, and was arrested and brought back to the station for secondary testing," Acting Inspector Smith said.

Despite those in the wrong, Acting Inspector Smith said "by and large, the majority of drivers were doing the right thing".