Gold Coast have been slapped with a $20,000 fine by the AFL after the club's fifth incident of a player making contact with an umpire this season.

Suns stalwart Daniel Rioli was found guilty of making careless contact with an umpire during the club's loss to Geelong last weekend.

The AFL Tribunal upheld the charge against Rioli on Tuesday night, with the league handing down the $20,000 penalty to the club on Wednesday.

The AFL warned all clubs before the season, and again in May, about the sanctions for repeated incidents of careless contact with an umpire, with five set as the threshold.

"This season we have continued to observe a high number of umpire contact incidents across the league," the AFL's football boss Greg Swann said in a statement.

"Amongst these instances of umpire contact, a number have resulted in significant injuries to the affected umpires.

"This is a trend in the game which we do not want to see continue."

Swann said if more Suns players were found guilty of careless contact with an umpire, fines would be given at the AFL's discretion.