AFL Western District has issued a statement saying it is aware of the matter and investigating.
PORTLAND police were called to an on-ground incident at the Dartmoor Recreation Reserve on Saturday.
A Portland police spokesman said officers attended at the ground just before half-time after a call was received at the Portland police station.
"Officers attended but whatever had happened was over and no one wanted to talk about it," he said.
"They stayed at the ground for the rest of the game but nothing else happened.”
It is understood there was an on-ground melee during the game that involved players, trainers, runners and there is an allegation that spectators were also on the playing surface.
Dartmoor unfurled its premiership flag on Saturday, but it was Heywood which scored a win 15.12 (102) to 10.8 (68).