Inspector Ewan Innes said: "The collision involved a northbound lorry and a pedestrian who we believe has crossed King Street from the east or beach side.
"I am particularly keen to trace two male pedestrians who were in the vicinity at the time of the collision and who may have crossed the road just prior to the victim.
"I would appeal to either of these persons to get in touch with us so that we can speak to them."
The road was closed for four hours while investigators examined the scene.