The league spoke to officials in the vicinity,including a security guard,according to two sources with knowledge of the incident who spoke confidentially while the investigation was still in progress.
Clarkson,who admitted to swearing and using inappropriate language,has since apologised to the AFL.
“I acknowledge that during the third quarter of Saturday’s game in a moment of frustration I lost my temper and swore while I was coaching from the bench,” Clarkson said in a statement issued by the Kangaroos.
“It was undisciplined by me and I have expressed my apologies to the AFL.
“As a club we can do without these distractions and as such I have agreed that it’s best if I remain in the coaches box on match days for the rest of this season.
“In the meantime,I’ll continue to seek support on how I deal with these moments.”