The ARL Commission has provisionally approved the working structure of the captain's challenge system to be introduced in 2020, with the system to be trialled in the upcoming All Stars and Charity Shield pre-season games.

A time limit of 10 seconds has been set for captains to contest a ruling, with teams to get one incorrect challenge per match.

Only the captain or acting captain may initiate the challenge, and only decisions that result in a structured restart may be challenged.

"This is an innovation which puts the fans first," said NRL head of football Graham Annesley.

"At the end of last season we conducted a fan survey, more than 20,000 fans responded, and the biggest issue they raised was the impact of an incorrect call on the game.

"The challenge system addresses those concerns and takes some pressure off our referees.

This is an innovation which puts the fans first Graham Annesley

"It also adds an additional element of excitement and tactics to our games. If a team gets a challenge wrong they will have no more challenges so it will need to be used strategically."

The system will be presented to the Commission for final approval after the trials in the lead-up to the start of the Telstra Premiership on March 12.

Who can challenge?

In most cases the team captain will be registering the challenge. Teams will nominate another player pre-game who will be able to challenge in the event the captain is off the field.

If both players are off the field at the same time, another player may be nominated to initiate a challenge.

What can they challenge?

Only decisions that result in a structured restart may be challenged. This includes scrums, penalty restarts, handovers, drop-outs and 20-metre restarts.

For penalties, the captain can challenge:

• decisions around stealing the ball,

• mid-air contact,

• foul play,

• obstruction,

• kick-chase offside

• and restart infringements (where there is a structured restart).

The captain may not challenge discretionary penalties such as ruck and marker infringements (like crowding, dissent and back-chat) or 10-metre offside penalties.

Captains can challenge any decisions around a change in possession other than forward passes (which cannot be ruled on by the Bunker).

This means as long as there is a structured restart they can challenge any knock-on or stripping calls, chargedowns, players making contact with the touch line or in-goal contact that determined whether a drop-out or 20-metre restart was awarded.

For example, if a knock-on is ruled against a team and the captain believes the ball was stripped or his player regathered the ball before it touched the ground, he may challenge as long as he does so within 10 seconds and before the restart takes place.

However, if he believes an opponent knocked on and the officials missed it, he cannot make a challenge during the run of play.

Captains can also challenge any decisions around point-scoring that are not sent to the Bunker – such as a try being awarded on-field, a try not being awarded and a restart ruled, or obstruction elements when a field goal is awarded.

Indigenous All Stars v Maori

Stealing the ball

The system has the potential to clarify interpretations around the current stripping rule.

The NRL has stated that under the captain's challenge system, a steal will only be deemed to have occurred if a player "demonstrates the intent to strip the ball", and that incidental contact with the ball that occurs while making contact with the player will not be classified as stealing the ball.

Every game there are instances where a referee must decide when a ball pops out if it was played at by a defender or just a loose carry, with some fans invariably disagreeing with the decision regardless of which way it lands.

The Bunker will also potentially be required to rule for the first time on when players peel off a multi-player tackle to allow a one-on-one steal to occur.

What happens after a challenge

Once a challenge is initiated, the Bunker will rule on whether the original call should be overturned. If it is, the challenging team will retain their challenge. If it’s not overturned, they will lose it and be unable to challenge for the remainder of the match.

If the Bunker is unable to determine whether the original decision was correct or incorrect, the challenge will be deemed unsuccessful, the original decision will stand and the challenging team will lose their challenge.

In the event of a successful challenge where there is no structured restart – for example the captain challenging a knock-on ruling and the Bunker finding no infringement occurred – play will restart via a play-the-ball to the side that would have been in possession if not for the incorrect decision.

After an unsuccessful challenge, play will restart in the manner originally decided by the referee; if there is no formal restart in these circumstances a play-the-ball will be awarded to the non-challenging team.