The Rugby Football League is looking into reports that referee Ashley Klein was pelted with missiles during the engage Super League match between Warrington Wolves and Hull FC at the Halliwell Jones Stadium on February 8.
The match - which Warrington won 32-20 - is also the subject of a police investigation into crowd trouble that flared both during the game and after the final whistle.
"We have launched an investigation into incidents that are alleged to have occurred inside the ground," said RFL media spokesman Craig Spence.
Hull FC were called to appear before a tribunal in November following crowd trouble in the Hull derby at Craven Park last July but they were found not guilty of failing to control their fans.
Hull KR were found guilty and fined £7,500, £5,000 of it suspended for 12 months.