THE AFL won't release vision of the in-house trials conducted by Hawthorn and Brisbane on potential rule changes to combat congestion.

Last Friday night, Port Adelaide chairman David Koch called for the AFL to release its vision of the Hawks and Lions trials, arguing that those two teams would otherwise have a four-month head start over the rest of the competition in adapting to any rule changes introduced for 2019.  

A League spokesman told AFL.com.au on Monday it would not hand over vision of the "closed sessions" to rival clubs.

"The AFL is happy to talk to other clubs about the purpose of the trials, what we're looking to do etc, but the vision itself is not something we would give to a competing club of how another club trains," he said.

At the AFL's invitation, Hawthorn completed match simulation at Etihad Stadium over the weekend of its round 12 bye, while the Lions undertook a similar session at the Gabba during their round 13 bye, with AFL field umpires adjudicating in both trials.

In the Lions session, set starting positions were implemented, with three players from each side having to be in the forward 50 and defensive 50 at every stoppage, while at centre bounces each side was required to have six players in the three zones of the ground.

Allowing players to take kick-ins 25 metres out from goal instead of the goalsquare was also trialed, but the last touch out of bounds rule and play on from backward kicks are among the other rule changes the AFL is considering.

Lions football manager David Noble said his club's session had produced "more open" football. 

"I didn't mind it. It certainly gives you a different look. There's more capacity for players to have one-on-ones," Noble told AFL.com.au last week.

"You've got numbers staggered up the ground rather than the condensation of numbers. With that distribution there's more space to work with. 

"It needs more work and more trialing and to have more data … it needs to be trialed in a full game."