A 55-year-old man is in a critical condition after a logging accident on the state's far north coast.

Police say a contractor working on private property at Whian Whian, near Lismore, was hit on the head by a branch that had been stuck in the forest canopy.

He was pinned for some time, but has now been flown to the Gold Coast Hospital suffering severe head injuries.

Protesters have been blockading the site for more than two weeks, claiming threatened species were not being properly protected.