AFL FOOTBALL operations manager Adrian Anderson says the recent rule changes to the interchange bench are proving far more relevant and realistic then the previous headcount scenario that was in place.

St Kilda and the Brisbane Lions were both penalised over the weekend after players crossed the interchange line before teammates had completely left the field of play.

Under the controversial new rules, the Saints and Lions both had to watch as the ball was returned to the centre for their respective oppositions to be awarded a free kick and 50-metre penalty.

St Kilda lost the lead in the final quarter on the Gold Coast last Saturday night as North Melbourne kicked a goal from Luke Ball overstepping too quickly, although the Saints regained the lead and won the game.

The AFL has defended its tough penalties for teams breaching interchange rules and reminded clubs that things could be far worse under the old system.

St Kilda and the Brisbane Lions were both penalised over the weekend after players crossed the interchange line before teammates had completely left the field of play.

Under the controversial new rules, the Saints and Lions both had to watch as the ball was returned to the centre for their respective oppositions to be awarded a free kick and 50-metre penalty.

St Kilda lost the lead in the final quarter on the Gold Coast last Saturday night as North Melbourne kicked a goal from Luke Ball overstepping too quickly, although the Saints regained the lead and won the game.

But the Lions' indiscretion, paid in the second quarter at the MCG on Sunday when Luke Power was too quick off the mark, was ultimately costly.

The resultant behind equalled Melbourne's winning margin.

But AFL football operations general manager Adrian Anderson, who saw both incidents, denied that the punishments were too stiff for the crimes.

Anderson said the penalties - introduced after round six, when Sydney briefly fielded 19 men in the drawn match against North - were acceptable compared to the "Draconian" previous rule, where sides could be stripped of their score if a head-count showed they had too many players on the field.

Anderson said the days of a captain calling for a headcount, if he believed at least 19 players were on the field was outdated and the penalties were too severe, as opposed to free kicks now being awarded.

"The old system was that the score would go back to zero if you had too many men on the ground and that was the responsibility of the captain to call a count," Anderson said at the MCG on Monday.

"We've realised that's no longer appropriate in this day and age and the responsibility on clubs is not to have 19 players on the field, so a free kick and 50 [metre penalty] or from the centre square plus 50 is a penalty that's a hell of a lot less than losing the entire score that you had for the game.

"It is fundamental that you have 18 against 18 at any one particular time."

Lions coach Leigh Matthews acknowledged Power's mistake had caused the infringement, but said the penalty could be considered too tough.

"We know the penalty, whether the penalty's too severe for the events, I guess that's an interesting judgement," he said.

"It's a pretty severe penalty for a minor offence, but the idea is there's only supposed to be 18 players on the field at any one time. That's the rule, anyway, and we all know the rule."

Meanwhile, new Australian International Rules series coach Mick Malthouse says one aspect he is looking forward to as the man in charge is being able to utlilise up to nine interchange players.

Malthouse is eager to see the interchange extended in the AFL premiership season.

"Just reading through the rules, if they're right, there will be between seven and nine interchange [players], which I've been pushing for some time, so it'll be the first time I've actually coached above the four interchanges, so I'm delighted about that as well," Malthouse said.