All Blacks coach Steve Hansen has a simple message – lay off the referees.

Rather than the captivating on-field action providing the early Rugby World Cup talking points, the tournament in Japan is, unfortunately, being dominated by a spate of controversial decisions and non-decisions.

Lengthy suspensions have been handed out as a direct result of a crackdown on any contact with the head but, then, there has also been a lack of consistency with England's Piers Francis escaping sanction for his high shot from the kickoff against the USA.

As Wales defeated Australia 29-25 in their gripping pool match, the television match official interference from New Zealand's Ben Skeen appeared to reach an all-time high, possibly as a result of all referees being put on notice.

The Wallabies were, rightly, furious with the decision by Skeen and French referee Romain Poite to penalise Samu Kerevi for his fend on Welsh playmaker Rhys Patchell, who got his tackle technique badly wrong.

From coaches to players and punters, frustrations are widely evident about the overt attention referees are commanding.

World Rugby is, perhaps, complicit in inflaming the current state of affairs after issuing a public statement which criticised the performance of its own officials after barely the first week of competition.

This is exactly where Wallabies coach Michael Cheika was coming from when he suggested referees are "spooked" about making the wrong calls.

World Rugby, intentions aside, may have only enhanced pedantic officiating by creating a culture of fear.

Hansen has gone the other way, offering a rare hand of support in the face of a concern that threatens to derail and completely overshadow this World Cup.

"All I'll say about the tournament and the referees, and I'm not going to say any more so please don't ask me, is they're under a lot of pressure," Hansen said after naming his team to play Canada in Oita next week.

"I talked before this tournament about how pressure can affect rugby teams and referees are no different so there's no point everyone climbing into them because it's not going to do anything other than put them under more pressure and it's not going to fix the problem."

Hansen also offered his thoughts on former Highlanders turned Japan coach Jamie Joseph, who has been immediately touted as the next All Blacks coach after guiding the host nation to their stunning upset victory over Ireland.

Interestingly, many have overlooked the savvy role Tony Brown has played alongside Joseph.

"Jamie Joseph is a very good coach. He didn't become one overnight just because he coaches Japan to beat Ireland.

"I always find it amusing, you beat someone then all of a sudden you're a super coach.

"I've got the world record for the most losses in a row and I've got the world record for the most wins in a row so what kind of coach am I?

"Coaching is a lot more than just the results. Is he good enough to be an All Blacks coach one day? I think he is, yep.

"Am I picking the next coach? No, so there's not much point even asking what my opinion is because those people that are appointing them won't take any notice of it anyway and probably rightly so."

Asked if he could learn from the way Japan exploited Ireland's vaunted rush defence and the prospect of meeting the hosts in the quarter-finals, Hansen said: "We'd be very silly if we didn't because they did plenty for us to think about. Their speed of ball was great. Their line speed was awesome. Time after time they just kept coming. They showed a lot of courage and intent and a lot skills.

"For the tournament what a major boost for the hosts who no one expected them to beat the No 2 ranked side in the world. They took it to them right from the word go and put them under extreme pressure and in the end got the result.

"It's important at world cups you don't think too far ahead because plans change all the time but if we have to play Japan we'll prepare accordingly and we'll expect what we saw the other day – them coming at us 100 miles per hour and wanting to create opportunities for fast ball."