AN official scorer will have 40 seconds to adjudicate on goal-line decisions under the AFL's guidelines for its video-technology trial.

The AFL has increased its use of video technology for the NAB Cup with a view to introducing it for the premiership season.

AFL football operations manager Adrian Anderson yesterday outlined protocols for the trial, but said players would not be able to call for a video referral.

Instead, a scorer - an umpires' department member - who has access to video replays can give input to miked-up umpires.

The scorer has 40 seconds to either give a concrete answer or refer it back to the umpire.

"There is no challenge system (for players), just when the umpires believe, or the official scorer believes, they can contribute. And they use their best endeavors to get it resolved," Anderson said.

"There is no over-turning of decisions, the consultation will occur before the goal umpire signals.

"We believe it may further improve accuracy, but our concern is not to slow the game down."

In last year's Grand Final, one of Sharrod Wellingham's goals deflected off the post. A Tom Hawkins' goal in the 2009 Grand Final also clipped the post, while debate continues over Anthony Rocca's point in the 2002 decider.

Anderson said there would still be room for physical contests in ruck work despite restrictive trial rules for the NAB Cup.

Ruckmen are banned from any contact before the ball leaves the umpire's hand at boundary throw-ins and throw-ups.

Brisbane Lions ruckman Clark Keating already has attacked the rules.

But Anderson said yesterday the trial hopefully would improve the spectacle of ruck work.

"There is a lot of holding and grappling that goes on, so we have had a lot of feedback about it and how it might improve the aesthetics of boundary ruck contests," he said.

"It will still be a physical contest, but the ruckmen just won't start the contest locked together. We had players who had played in earlier eras ... urge us to have a look at it."

NAB CUP TRIAL RULES

*Video technology used in goal-line decisions, with the official scorer to be involved in the consultation process.

*Ruckmen cannot make contact with their opponent until the ball leaves the umpire's hand.

*Interchange system has two interchange members and two substitutes for week one of the NAB Cup.

*An umpire can pay a free kick if a player drags the ball under his opponent, or if a player holds the ball in when an opponent is trying to knock the ball out.

*A free kick is paid against the team which last kicks or handballs the ball over the line, provided no one else touches the ball before it goes out of bounds. Players walking the ball over the line are also penalised.

*Boundary and goal umpires can pay free kicks for holding and high contact.

*The nine-point super-goal from outside 50 metres.

Originally published as Video ump to fix goal-line bloopers