A cyclist has been killed in Victoria after a crash involving a truck.

Police say the truck was heading towards Colac on Colac-Ballarat Road on Friday morning when the collision with the cyclist happened.

Paramedics performed CPR on the cyclist for about 30 minutes but the man, believed to be in his 40s, was pronounced dead at the scene, an Ambulance Victoria spokesman said.

The crash, just after 6.30am, has closed the road in both directions.