On 24 January, highway patrol stopped a 42-year-old man who was allegedly speeding on Mt Dandenong Tourist Road.
Police said the man had a stolen firearm, firearm parts and ammunition in his vehicle and he returned a positive reading for illicit drugs.
The man was arrested and will face firearm and drug driving charges.
A 56-year-old man returned a positive result for illicit drugs after being stopped driving on Sherbrooke Road, Sherbrooke on Australia Day, 26 January.
The man will attend court and appear before a magistrate because of a prior offense for a similar matter.
The penalty for a subsequent offence is a minimum 12-month licence suspension.
