The AFL hope their new substitute system will stop the speed of the game escalating to a "new and dangerous level".

But league operations manager Adrian Anderson denies they have a particular number of interchanges per game in mind under the new system.

They have released details of the controversial new substitute procedure, which was announced late last year.

While opinion is divided, the AFL say they need to stop the increasing trend over the last few seasons of clubs using interchanges as a tactical ploy.

"The whole idea of introducing a sub was to prevent rises in interchange (numbers) taking game speed to a new and dangerous level, and the congestion that would result," Anderson said.

"It will have the effect of limiting the interchange and there's been some talk about 'aw, it's designed to stop it at 80' - that's not right.

"It's about preventing it going to a new level, which would have created more congestion and, we're told, more injuries as well."

Under the new system, a club will nominate one of their four interchange players as the substitute when the team sheets are lodged about an hour before the game starts.

The substitute must wear a green vest until he is activated to play and the team-mate he replaces must wear a red vest.

The player who comes off for the substitute cannot return for the rest of the game.

Their interchange can happen at any time during the game and does not have to be injury-related.

If a club sends a substitute player onto the field before notifying the interchange steward, the opposition club will receive a free kick and 50m penalty.

"They (clubs) have been involved in helping us come up with the mechanics of how it will work ... it's quite a simple system, but one I'm sure that will work fine," Anderson said.

The league examined various options, including a cap on the number of interchanges, before going with the substitute system.

Clubs will continue to have two substitute players on their benches during the NAB Cup pre-season competition.

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