THE TREND of shepherding the man on the mark has been ticked off by the AFL umpires' department.

Hawthorn is a regular exponent of the tactic and used it several times in its qualifying final loss to Geelong.

AFL head umpires coach Hayden Kennedy told AFL.com.au's Whistleblowers program the practice is legal as long as the player making the block is standing behind the man on the mark.

"You are allowed to step in and put a passive block on a player," Kennedy said.

"If a (player) is standing on the mark and another (player) wants to come in shepherd, he has to start behind (the mark), because otherwise we'd have two on the mark and that's against the rules," Kennedy said.

"Once the umpire calls play on, the player is allowed to take that step (forward) and put that block on.

"But if he makes solid contact with the player on the mark that would become a free kick or a hold and the umpires are well aware of that."

If a player employing that tactic is standing next to the man on the mark, Kennedy said the umpire can't play a free kick under the current rules and slow ball movement should be a deterrent in itself.

"The penalty at this stage is a stoppage in play," he said.

"The umpire will stop the play, he'll clear the player out and then reset play and that becomes a real slow play for the (offending) team."