BENDIGO police have warned residents they will be out in force on Tuesday night after catching nine drivers affected by drugs since Boxing Day.
Police will have a highly visible presence from 7pm.
Highway Patrol Acting Senior Sergeant Della Nihill said three offenders refused to return to the station for further testing.
"The remaining six tested positive for methamphetamine," she said.
"Three out of that six were affected by cannabis and methamphetamine.
"Eight of those drivers were caught in Bendigo and five were probationary drivers."
The drivers who refused to return to Bendigo Police Station will receive a summons to appear in court.
The other six drivers will be charged following the outcome of further testing.
Acting Senior Sergeant Nihill said police were encouraged to receive training in drug testing.
"Catching nine drivers affected by drugs is more than average," she said.
"That increase is because more police are trained how to conduct drug tests."
Senior Sergeant Craig Gaffee said police would be out in force on New Year's Eve and would be conducting random breath tests.
"Police will have a highly-visible presence from 7pm until about 5am the following morning," he said.
"We want everyone to be able to enjoy themselves safely.
"Police will be breath testing drivers and foot patrols will target antisocial behaviour."