THE AFL has tweaked two rule interpretations for the upcoming season, with two-on-one marking contests to be strictly policed to preserve contested grabs as a feature of the game.

And after a period of debate in 2014, there will also be a firmer interpretation of holding the ball, with umpires being coached to crack down on players with prior opportunity.

Umpires coach Hayden Kennedy has been briefing clubs on the changes ahead of the NAB Challenge, with players welcoming the stricter prior opportunity interpretation.

There have been questions, however, around the marking contest adjustment for two-on-one scenarios.

Kennedy said the two cues for umpires to pay a free kick in marking contests would be if a player moves off the line to prevent an opponent from contesting the ball, or if a player shepherds a player from contesting the ball.

"The game features spectacular high marking and contested marking and what we're really concerned about was the contested marking," Kennedy said.

"So what we're looking at this year is a stricter interpretation of two v one."

Players will still be allowed to hold their position in a marking contest or hold their line, even if that prevents their opponent from contesting the ball.

Kennedy said body contact and strength in marking contests would "certainly still be part of our game".

Retired St Kilda midfielder Lenny Hayes, who has a role supporting the Laws of the Game Committee, said he didn't expect the change to have a big impact on the game.

"I think this type of scenario only happens once or twice a game, so once the players are aware of the cues the umpires are looking for, they'll be able to adjust the way they play the game," Hayes said.

"I don't think it's a major shift in the way the rule's going to be adjudicated.

"From a players point of view you still want to be able to have a free run and jump at the ball."

The stricter interpretation of the holding the ball rule has been welcomed by clubs, with the umpires adding clarity to how they would determine prior opportunity.

Kennedy said the three cues umpires would use were:

- If a player with the ball is balanced and steady (has had reasonable time)

- If a player has chosen to take a player on (tries to fend or evade)

- If a player has had an opportunity to dispose and chooses not to

"They're the three things we're going to be coaching our umpires on," Kennedy said.

"It is a fine line, but we need to reward the tackler and we have to make every opportunity for the ballplayer to take possession as well."

Hayes, who has also been briefing clubs on the new interpretations, said players had "100 per cent" endorsed the stricter policing of holding the ball.

"More than ever your first option is your best option and that's the way they're going to be coached," he said.

"I think it's a good rule."