Blues coach and former All Blacks captain Tana Umaga has given a cautious endorsement of rugby's controversial new tackling laws.

Famed for his hard-man approach and his timeless quote about "it's not tiddlywinks" after a run-in with a referee over a high tackle, Umaga admitted the law changes had already forced a revamped approach to this year's Super Rugby competition.

He revealed his Blues squad had analysed several video incidents from last weekend's round of Northern Hemisphere professional matches which were the first played under the new laws introduced on January 3.

Umaga is taking a philosophical approach to the changes, agreeing they are necessary and that rugby may even be a better game once "we get through the bedding down process".

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"Our worry is more about interpretation really," he told Newstalk ZB host Tony Veitch in a radio interview to be aired today.

"We understand why the changes have come into play, with the studies on concussions and the head injuries the game has had. We're going through that ourselves at the moment with one of our players who is still suffering symptoms from concussion from the Mitre 10 Cup.

"So we totally understand and agree with the line that is being taken. But as always, it's about what is going to happen from here.

"We've shown clips to our players on what is acceptable and what is going on in the north at the moment with yellow cards, penalty tries going on, and we're already starting to incorporate changes.

"Some players probably thought they were OK in the past in how they tackled but now they're not.

"Some of our players just have to understand they've got to change their tackling technique. They have to get lower so they don't get up around that area where we don't know what is going to happen.

"If that's the way it's going to be ruled, we are just going to have to adjust. We have to devise ways to cope."

Umaga predicted a "feeling out period" early in Super Rugby and said New Zealand franchises had an advantage in watching what was unfolding in the northern competitions.

"It's like every rule change. There's always conjecture and it requires a bedding down period. Hopefully it doesn't take too long.

"Players will have to go lower. We've already started that with our players of trying to get them into a mindset of going lower.

"For some, it's a little bit foreign. That's my concern. We are trying to change guys who have been tackling front-on for quite a while.

"But we all need to adapt and adjust to what has been given to us."

Umaga said rugby may even blossom as a spectacle under the changes.

"It may open up more opportunities for more flowing rugby. If everybody is going low, offloads could be more prevalent," he said.

"So it could add to the attacking game, which isn't a bad thing."

Umaga also felt the All Blacks did not need to fear the changes might impact their global supremacy.

"I still think we are very good low tacklers and very strong in that area. So if we make good, low, dominant tackles, we're still going to be very strong in the contact area," he predicted.

"From an attacking point of view, it does give us another opportunity to keep the ball alive more, which is what we want to do. That could be something that comes with it."

Umaga, now into his second year with the Blues, is excited about Super Rugby.

"I was finding my feet in my first season and we hadn't worked together as a management team before.

"But now we've had that 12 months, and we've brought some new players in who I have worked with previously and who I believe will make us better.

"I'm pretty excited about what is ahead."

Umaga confirmed Sonny Bill Williams is on track to return from an Achilles tendon operation in March or April.

"He's looking amazing at the moment and is on track with his rehab. He's very passionate about getting back and on to the field for us."