THE AFL will soften interchange infringement laws this year with fines to be imposed for players who step fractionally outside the interchange gates.

A free kick and 50-metre penalty would only apply if a player misses the interchange gates by a metre or more.

The AFL is trialling a different interchange set-up during the NAB Cup with a view to implementing the change in the home-and-away season, AFL football operations manager Adrian Anderson confirmed.

Under the change, teams no longer share one interchange box but have their own smaller yellow-marked interchange boxes on the boundary, with a white line one metre further along the boundary.

Players who step outside the yellow boxes will incur a fine but not suffer a free kick and 50-metre penalty, as has been the case. The tougher penalty would still apply if a player ran outside the white markers.

''The purpose of the change is to make it less congested, clearer and make it less likely that players will give away a free kick for a minor step over the line,'' Anderson said. ''If you miss your gate only by a small margin then it's a financial penalty, but if you miss your gate by a lot - and that means by a metre or more - then there is a free kick. So it will make it harder for players to give away those free kicks for a minor step over the line.

''The feedback from the weekend from the interchange stewards from the AFL and the clubs was that it worked very well.

''It's still the 15-metre area it has always been, but within that area are the gates for either team. We are looking at introducing it for this season.''

The stricter interpretation of the interchange breach, which came into place for the 2008 season, was immediately unpopular with clubs, which considered the level of punishment too great for a player missing the gate by a step and having no impact on the game. In last year's elimination final at Etihad Stadium, St Kilda's Justin Koschitzke infringed at the interchange resulting in Sydney being given a free kick and 50-metre penalty. Ryan O'Keefe kicked a goal from the free kick.

''It is a huge penalty for going that far over the line,'' Bulldog player Daniel Giansiracusa said at the time.

In another match earlier last year, the Swans were on the receiving end when they gave up a 50-metre penalty that resulted in a Carlton goal and a seven-point lead in a match the Blues won by 16 points.

Anderson said he was otherwise satisfied with the way other rule changes being used in the NAB Cup - such as the no contact between ruckmen at stoppages - had operated, but were not in line for being implemented in the season proper.