A cyclist has filmed the terrifying moment a truck driver threaten to "smash" him shortly after allegedly trying to run him off the road.

The Yarraville man, who does not wish to be named, was riding two-abreast in light traffic on an overpass on Footscray Road, Footscray, about 9.30am on Saturday.

He claims the truck suddenly swerved within 30 centimetres of him.

"This truck came alarmingly close," he said. "I got the biggest fright."