NSW police are marking what would have been the 11th birthday of William Tyrrell, as the force continues to attempt to crack the case of the missing boy.

William was three when he disappeared from his foster grandmother’s home in Kendall, on the NSW mid north Coast in September 2014.

He was wearing a Spider-Man outfit the day he vanished.

A high-profile search for the body of the missing toddler in Kendall wrapped up last December without any obvious breakthroughs, but detectives are not giving up.

“The NSW Police Force remains committed to finding William Tyrrell and investigations by the Homicide Squad’s Strike Force Rosann are ongoing,” the force said in a statement on Sunday.

“Strike force detectives are continuing to conduct interviews and other investigative activity, including those under Coronial Orders, as well as reviewing all material with the assistance of various experts.”

A $1 million reward for information leading to William’s recovery still stands.

-AAP