REFEREE Wayne Barnes has called for patience as new scrum laws that have attracted criticism before the season has even started are trialled in the northern hemisphere.

The adjusted rules force opposing props to bind fully onto each other before engagement and the scrum will only be active when the ball is fed, which scrum-halves must now do straight down the tunnel.

While the initial focus of the laws was to enhance player welfare, their introduction has been given the added importance of overhauling an area of the game that was being significantly undermined by repeated resets.

Leicester director of rugby Richard Cockerill has been the most outspoken critic of the changes, asking why they were devised without consulting Aviva Premiership coaches, questioning their safety and suggesting they have only served to create a different type of ‘‘mess’’.

Barnes has been visiting Premiership clubs throughout pre-season to assist them in implementing the rules and insists that the general reaction has been positive ahead of the start of league competition tomorrow night.

‘‘There has to be buy in from everyone for this to work and what’s been good is that we’ve gone into clubs and there seems to be a will among players and coaches to make this work,’’ he said.

‘‘Obviously there will be teething problems and I’m sure we’ll see that this weekend when the season starts.

But we have to make sure this works so that we get better scrums and outcomes.”

The International Rugby Board (IRB) commissioned research overseen by their scrum steering group costing £500,000 that examined all levels of the game from international to youth rugby.

The results were the same at every level. By having players bind before they engage, the force of the two packs coming together – known as ’the hit’ – is reduced by 25 per cent.

The referee then waits until the set-piece is stable before instructing the scrum-half to put the ball into the scrum straight with a call of ’yes nine’, at which point the packs can push.

Barnes did little to refute this up by warning that referees will adopt a zero-tolerance policy from the start.

‘‘If a player continues to do something that we told them in pre-season they shouldn’t, there have to be sanctions,’’ he said. ‘‘This is a seasonlong trial. We don’t want to start off week one being very harsh, then by week 20 everyone’s forgotten about it.”