The AFL is set to trial four new rules in this year's NAB Cup, with boundary umpires handed the opportunity to award free kicks from stoppages.

The NAB Cup has been used as a testing ground for any number of new rules over the years and the AFL has ramped up its experimental take on the pre-season competition by trialling several radical rule changes.

The biggest shake-up sees the four boundary umpires given the power to award free kicks for infringements off-the-ball at stoppages. That rule was trialled in a Western Bulldogs intra-club match over the weekend, with two free kicks awarded for off-the-ball infringements.

AFL football operations manager Adrian Anderson said it was difficult for a field umpire to detect incidents of holding while bouncing the ball, while the other field umpires were often too far away.

"The boundary umpire is an extra set of eyes to help detect holding at stoppages. The boundary umpires have been trained up over summer. They are looking forward to the challenge," he said.

"The NAB Cup gives an opportunity to try and do things better. This issue of holding at stoppages is again one which the coaches and clubs have brought up with us. We want to trial something in the NAB Cup to see if the boundary umpires can assist in dealing with the issue."

The other rule change which is likely to court contention and controversy is where a player drags the ball in under an opponent in a bid to win a holding-the-ball free kick. If a player deliberately pulls the ball in, in this manner, the free kick will go against that player for holding the ball.

"The whole spirit of the holding the ball rule is to require players to keep the ball in play and to keep moving, What we've seen is a number of examples where the tackling player drags the ball underneath his opponent looking for a free kick," Anderson said.

A change to the advantage rule, which sees play-on called when a team has won a free kick but the play is to their advantage anyway, will also be trialled with the onus on the player, rather than the umpire, to determine if it is advantageous to play on.

If a player chooses to play on and turns the ball over with a poor disposal, the ball will no longer be brought back to the position of the initial infringement.

"Under the current advantage rule, the umpire has to decide whether there's an advantage or not in that situation," Anderson said. "What the trial is about is putting it in the player's hands to decide whether he believes if there is an advantage."

The other rule change sees the no-go zone, which has been used at centre bounces to prevent players colliding with umpires, now introduced around the ground. Any player who enters the zone behind the umpire at, or after a stoppage will be penalised.

Anderson said that none of these rules will be introduced immediately into the season proper but that their effectiveness will be assessed to see if they warrant further consideration.

Anderson also failed to guarantee the future of the NAB Cup beyond 2011, when the current broadcast arrangement finishes.

"That's something to be resolved. Obviously having extra teams in the competition raises issues," he said. "The NAB Cup remains in its current format for the duration of this broadcast agreement. Having an extra team involved will create a difficulty in terms of the draw."