The NRL has launched an investigation into banned Cronulla coach Shane Flanagan's appearance at Remondis Stadium at Saturday's trial between the Sharks and Wests Tigers.
Flanagan's appearance at the game is in blatant violation of his 12-month suspension handed down in December in regard to governance issues at the club in 2011.
Flanagan is appealing the ban.
In a statement on Sunday the NRL issued Flanagan with a please explain for sitting in a corporate box to witness the Tigers' 28-22 win in both clubs' final pre-season game.
"The NRL is seeking an explanation from Cronulla Sharks and Shane Flanagan to understand the circumstances regarding Mr Flanagan watching last night's trial match at Shark Park from a sponsors corporate box," the game's governing body said.
"Preliminary findings issued by NRL Chief Executive Officer Dave Smith in December 2013 prohibit Mr Flanagan from directly or indirectly being involved with the club.
"Chief Operating Officer Jim Doyle confirmed today that the NRL will write to both parties to seek a written explanation.
"This information is required to assess whether there has been a breach of the suspension notice."
Flanagan told News Corp that he viewed the game from a corporate box at the back of the Andrew Ettingshausen Stand.
"I've just watched my son, Kyle, play earlier in the Harold Mathews and decided to stay and watch the other grades," Flanagan said.
