Canberra motorists are being warned to brace for traffic disruptions as planned protest marches move through the Civic and the parliamentary precinct on Australia Day.

ACT police say the first march is expected to begin from Civic at 10am, before crossing the Commonwealth Avenue Bridge and heading to Parliament House, finishing out the front of Old Parliament House. Commonwealth Avenue will be closed to traffic for a short time while the group passes through.

A second protest march is expected at midday, starting at Parliament House and finishing at Lennox Gardens in Yarralumla.

Police have warned that minor traffic disruptions may occur as the marches move through the area, urging drivers to consider alternative routes if they want to avoid delays.

Police said they supported the right to peacefully protest but warned that disruption of business activity or any criminal behaviour would not be tolerated.

Protests planned amid calls for unity on Australia Day