There are grave concerns for a 57-year-old man who fell overboard near Rottnest Island.

Peter Tuohey, of Alexander Heights, was returning from Rottnest Island to Hillarys Boat Harbour with his wife and friends on Sunday when, around 4pm, they noticed he was missing.

Twelve boats and a helicopter were suspended about midnight but the search will resume at 8am on Monday.

96FM Perth