THE AFL will act to prevent a repeat of the mix-up that led Sydney to have an extra man on the ground in the final stages of Sunday's drawn game with North Melbourne.

The Swans were fined $50,000 this week, with half suspended for two years, after a league investigation found Sydney debutant Jesse White was the extra player on the field late in the fourth quarter.

AFL football operations manager Adrian Anderson said the league would "not tolerate a situation where clubs have excess players on the ground" and would amend the rules concerning extra players. Under AFL rule 5.5.1 only the opposition captain can call for a head count if he believes the opposition has too many players on the ground.

This week's investigation found the interchange stewards and the emergency umpire at Telstra Dome both knew an extra player was on the ground, but under the rules were powerless to act.

"We will be changing these rules to make sure this situation cannot evolve in the future and, if it does, further on-field sanctions can apply in addition to what applies at the moment," Anderson said.

He said changes to the bench could come into effect before the end of the season, but would not speculate on any possible changes, or any on-field penalties that could apply. In the frantic closing stages of Sunday's game the Kangaroos had the option of calling for a head count, but chairman James Brayshaw said doing so would have been embarrassing.

Brayshaw met with Anderson yesterday after revealing he was angered by the AFL's suggestion the Kangaroos could have avoided the controversy by calling for a head count.

"I've made it very clear to the Kangaroos (that) I'm not criticising the Kangaroos for not doing so," Anderson said after yesterday's meeting.

"That's a perfectly legitimate choice for them.

"But the option under the rules as it stands at the moment, for a match to be altered, is for the captain to call for a count. It is relevant in the consideration of the matter that they did not invoke that."

Sydney coach Paul Roos was surprised by the Kangaroos' reaction this week, particularly as coach Dean Laidley said after the match he believed it was an honest mistake.

"They must have had a meeting when they all decided what they said wasn't correct," Roos said.

"That's their decision to take the tack they have since (Tuesday) lunchtime, we've moved on. I thought they handled the situation really well after the game and things changed significantly since then, for what reason you would have to ask them."

Roos said there was "probably some discussion that needs to take place" about how the interchange bench operated and admitted, even from his new vantage point nearby, he did not know how it worked.

"I've never really thought about how it is managed," he said. "I feel for the interchange guy, it must be impossible for him to be able to pick up everything.

"It's certainly a bigger issue than what it's ever been with the amount of rotations now."

Roos said until he spoke to White about the fiasco, the 20-year-old was still confused about what went wrong.

With MICHAEL GLEESON