The RFL have begun an investigation into alleged racist behaviour by fans during Wakefield Trinity Wildcats’ home game against Bradford Bulls last weekend.
Wildcats had already launched their own probe following claims of disorder among spectators.
Wakefield won the First Utility Qualifiers tie - which attracted a crowd of 3,985 - 48-18 to boost their hopes of remaining in Super League and leave Bulls with a mountain to climb in their bid for promotion.
An RFL spokesman confirmed an investigation has begun into alleged offensive chanting by some fans.
The club had earlier issued a statement saying they were working with the police, RFL and steward supplier Radius to get to the bottom of what happened on the terraces.
Wildcats chairman Michael Carter said the club will cooperate fully with the RFL’s inquiry and he stressed offensive behaviour will not be tolerated.
“If we do find instances of fans having been guilty of disorder, they will be banned,” Carter said.
“We are not having it.”
Carter said the allegations relate to a small number of fans and he added: “The overwhelming majority of both sets of supporters mixed freely on the day and created an excellent atmosphere.”