Motorists will need to slow down along two sections of the Captain Cook Highway near Mossman where the speed limit is set to be reduced.

The speed limit will be changed to 80km/h near the Mossman-Mt Molloy Road intersection and 60km/h between Shannonvale Road and Parker Creek, immediately south of Mossman township.

Transport and Main Roads North Queensland Regional Director Sanjay Ram said the speed limit changes were part of the $2.4 million project of safety treatments along the Captain Cook Highway between Port Douglas and Mossman.

"We are changing the speed limit to improve safety for all road users and provide a more consistent speed environment into Mossman," Mr Ram said.

Variable message signs will be in place on the approaches to these locations to ensure motorists are aware of the changed traffic conditions.

These safety works are part of the Queensland Government's $112 million program being delivered state-wide as part of the Targeted Road Safety Program.

This program helps to reduce trauma on roads by providing long-term improvements to traffic flow and safety at key intersections.