Two motorists were caught breaking the law during a one-hour police operation monitoring traffic along Howard Street near the Epsom Primary School.

Between 2.50pm and 3.50pm police detected two motorists travelling more than 20kmh over the limit.

A third motorist was caught travelling at 59kmh.

Penalty notices were also issued for people crossing the double lines and not wearing a seat belt.

Sergeant Geoff Annand of the Bendigo traffic management unit said police had received numerous complaints about motorists disobeying the road rules, particularly in the 40km school zone around the Epsom Primary School.

He said the operation was a response to those complaints, and police would continue to monitor all school zones.

School zones are in place from 8am to 9.30am and 2.30pm to 5pm on school days.

Some school zones have permanent 40kmh speed limit.

A 23-year-old Campbells Creek woman was fined $234 after she was caught smoking in a car with two children in the back seat.

The woman was caught travelling along the Midland Highway at Castlemaine at 6.15pm.

Police said she had a six-year-old and one-year-old child in the car with her at the time.

Since January 1, police can fine anyone found smoking in a motor vehicle with children under 18.

In Victoria the maximum penalty for an individual found smoking inside a car with a child under 18 is five penalty units ($584), with an infringement penalty (on-the-spot fine) of two penalty units ($234).