The controversy has again erupted in wake of Lindsay Thomas' actions on Friday night, where the North Melbourne small forward was awarded two free kicks and converted these into goals during the Kangaroos' 26-point loss to the Sydney Swans at the SCG - their first defeat of the season.

He was given a free kick in the opening term and in the second, having dropped his knees and lowered his centre of gravity when tackled, resulting in a high free kick awarded against the Swans.

Swans youngster George Hewett was also given a free kick for a controversial head-high decision in the first quarter, having dropped his knees while tackled.

Kangaroos coach Brad Scott defended Thomas but Brereton made his feelings clear about the small forward - and other players - on Saturday.

"Last night we broke new ground ... I have known Lindsay Thomas. Lindsay was in a pack, surrounded by two other bodies, and he had an exit passage straight ahead of him - put the runners on, sprint out that passage and you snap away," Brereton said.

"For the first time we broke new ground in this. He thought: 'No, I am going to seek out the tackler'. He actually went into reverse, got lower in reverse, and drove up into the tackle from behind under the armpit.

"It was new ground and he actually thought: 'Where is the tackler, I want the tackler, because I can milk a free out of this'. That is not the spirit of our game."

Thomas found himself involved in a similar tackling controversy last season.

AFL operations manager Mark Evans said on Saturday the league did not have any plans to make major changes to the rule.

He said the AFL Laws of the Game Committee had been asked again this year whether there was a way to eradicate the problem, which he deemed was a "really complicated thing".

Evans insists the duty of care must remain with the tackler, insisting it was better "to have errors of a couple of free kicks that you don't like" than dealing with "broken jaws or concussions".

In June last year, the AFL enforced a stricter interpretation on players who lead with their heads to draw a free kick for high contact. This was tightened to rule a player who drives or leads with his head into an opposition player will be deemed to have had prior opportunity.

Of the 40 free kicks given on Friday night, 16 were for head-high tackles. Swans coach John Longmire said the AFL needed to analyse the head-high issue at the end of the season.

"This will be looked at - it's not an easy one but I am sure it will be looked at," he said.

Brereton said Geelong skipper Joel Selwood had been the master of the tactic.

"This is a go-to action - and we'll call Joel Selwood the champion of it. He has perfected it. He is brilliant at it. He doesn't like me for what I have said about it but that's fine, I can wear that," he said on SEN.

"He sags at the knees, he lowers his height, rather than ducking - the tackle is aimed up between the breast and hip. By lowering his height at the last second, that tackles goes above the breast and all he has to do with that power he has in his arms, slide that tackling up over his shoulder and he gets a free kick."

Brereton listed other players he believes are guilty of milking head-high free kicks.

"Lindsay does it, [Scott] Pendlebury does it, [Dylan] Grimes does it, [Paul] Puopolo does it. West Coast are very, very good at it. [Luke] Shuey does it - he is a genius at it," he said.

Brereton new players into the system, such as Brisbane's Rhys Mathieson, had already mastered the art.

"We are now seeing players come into the competition and their go-to evasive action is to lower their height. There is a kid called Mathieson at Brisbane - he got six free kicks for lowering his height and ducking into the tackle," Brereton said.

"In fact, a coach from Brisbane said, smirkingly before the game: 'You watch how many head-high tackles this kid gets. That's his go-to action when he comes in'."

Scott defended Thomas on Friday night, declaring he hadn't broken any rules and wasn't the only player to adopt the tactic.

"There'll be cowards out there that single out individuals, but every player in the competition tries to do it," he said.

"So until the rules change, the players will keep doing it. While they continue to get paid, then players will keep doing it.

"They make the decision to do it, but again they're being incentivised because the free kicks are being paid."