Backs will be banned from packing into scrums and the NRL Bunker will review tries while the goal kicker is preparing for a conversion attempt under experimental rules to be trialled in matches with no impact on the NRL finals.

NRL CEO Andrew Abdo announced on Tuesday that Thursday night's Broncos-Cowboys match and Sunday's Warriors-Manly clash would be used to pressure test possible rule changes for next season.

They include:

  • Use of the "six-again" rule for 10-metre infringements
  • Handover for kicks into touch rather than a scrum
  • Nominated forwards only to pack in scrums
  • Change in the Bunker referral process to reduce stoppages

"It is clear the current process around scrums and the Bunker could potentially be better," Abdo said. "We are also looking at ways in which we can reduce stoppages without compromising the accuracy of the Bunker."

Scrums have long been the source of frustration for fans and many in the game, including ARLC chairman Peter V'landys, and former Penrith and England hooker Mike Stephenson last month told NRL.com they should be scrapped completely.

Every try from round 19

Front-row great Steve Roach was outraged that Sydney Roosters halfback Kyle Flanagan packed down as a prop in the round 9 match against North Queensland and V'landys recently suggested that credibility could be restored by banning backs from scrums.

The ARL Commission agrees and has approved the trialling of rules to ensure that occurs, with only players nominated as forwards on the team sheet 60 minutes before kick-off able to participate in scrums.

Interchange players can only pack into scrums if they have interchanged with a forward, with the referee and touch judges to monitor the players packing down.

If match officials detect that any player other than a nominated forward packs into the scrum, the referee will delay the feeding of the scrum and instruct the team to alternate positions, while the scrum clock continues to run.

If the scrum clock expires as a result, a full penalty will be awarded to the opposing team.

"We are a sports entertainment business," Abdo said. "It is important to continuously test innovative ideas, aimed at a better fan experience.

"This weekend is a great opportunity to test the practical application of some of the refinements which have been raised during the year."

NRL head of football Graham Annesley flagged the idea of the Bunker being able to overrule a try that had been incorrectly awarded during his weekly media briefing on Monday after touch judge Phil Henderson wrongly advised referee Ashley Klein that South Sydney winger Jaxson Paulo had scored last Thursday night.

Annesley had been in the Bunker when review official Henry Perenara attempted to warn to Klein to refer the try after Paulo's foot glanced the touchline before he grounded the ball but once the try was awarded it could not be overturned.

However, the referees in the Broncos-Cowboys and Sea Eagles-Warriors matches will be told not to refer any try they believe had been scored as the Bunker will review it while the goalkicker is preparing his conversion attempt.

Should the real-time review indicate the possibility that a try had not been scored, this will be proactively communicated to the on-field referee who will stop the conversion process until a final decision is made.

When the on-field referee is unsure as to whether a try has been scored it will be referred to the Bunker as normal.

"The Commission's focus is to ensure our games are as entertaining and free-flowing as possible for our fans," Abdo said. "Like we have in previous seasons, we will use games which will have no impact on the top eight to test the potential rule changes.

"We will obviously also take on board feedback from the players and clubs involved and report back to the Commission during the off-season."

Other experimental rule changes aimed at reducing stoppages will result in the awarding of six-again call for off-side infringements by defending teams and a play-the-ball re-start instead of a scrum where the ball or an attacking player has gone into touch.

With the exception of a 40/20 or 20/40 kick, play will resume with a play-the-ball by the non-offending team 10 metres in from touch, opposite where the ball entered touch, but no closer than 10 metres from a goal line.

For offside infringements, the referee will restart the tackle count by verbally and physically signalling six-again.

This applies to players who do not retire 10 metres to the point set by the referee, or those who do retire 10 metres but move forward before the ball clears the ruck, as Canberra five-eighth Jack Wighton did in last Sunday's match against the Warriors.

Wighton was sin-binned for repeated infringements and he still could be under the experimental rules.

Annesley backs Wighton sin bin, responds to Ricky

A full penalty will be awarded for professional fouls, repeated infringements or where the off-side breach has resulted in the ball being lost.

A full penalty for a professional foul or repeated infringements, will result in the offending player being sent to the sin bin.

If the team in possession deliberately breaks down play in an attempt to convert the "six-again" call into a full penalty, the referee will order a scrum with the loose head and feed to the opposition.