Ian Foster explains reasoning behind the All Blacks halfback and front row selections

All Blacks head coach Ian Foster has explained the reasoning behind the toughest selection decisions he and his colleagues had make for their 36-man squad to face Ireland next month.

Foster pinpointed halfback and the front row as the trickiest positional groups to pick for the selectors, with 78-test veteran TJ Perenara and Chiefs captain Brad Weber the headline names to have missed out.

Perenara and Weber were both heavily involved in last year's All Blacks side, starting multiple games each as Aaron Smith stayed behind in New Zealand when the team travelled to Australia for the Rugby Championship before returning late on their end-of-year tour.

Whilst Smith retained his place in the newly-named squad, his uncapped Highlanders teammate Folau Fakatava was a new selection, while in-form Blues star Finlay Christie has risen up the pecking order to supplant Perenara and Weber.

"We spent a lot of time on the nines, and probably the front row," Foster explained on Monday of the toughest positions to select.

"They were the two main areas we had the most debate. Clearly you have debates about everything, but particularly in the nines, we had five nines playing really well.

"This is just a really good chance to see what Folau and Finlay can bring. We like what we see and it's a good opportunity."

However, Foster hinted that Perenara and Weber may still get a chance to play Ireland as part of the Maori All Black squad, which will be named on Tuesday.

"There's another team being named tomorrow and maybe there's a chance for others to put their hands up."

Adding cloud over the halfback group is the fitness of test centurion Aaron Smith, who is battling a groin injury ahead of the first Irish test at Eden Park on July 2.

"We hope so," Foster said of Smith's first test availability before revealing that star fullback Jordie Barrett is also in doubt due to a knee injury.

"We're not sure at the moment, his groin is still a bit niggly. The two guys at the moment, him and Jordie, are both a bit 50-50 but we won't know for sure until we get our hands on them."

Foster was reluctant to talk about Perenara's omission, but noted that the coaches have a plan for every All Black not selected to contend again for future selection.

That suggests Perenara, and others, could yet feature later in the year during the Rugby Championship or on the end-of-year tour.

"I'm not going to talk specifically on those conversations in detail," Foster said of Perenara's omisison.

"What I would say is, I think I had nine conversations yesterday with All Blacks from last year who weren't named today, and they were really tough, but they are great men. You could feel the passion on the end of the phone call.

"Each of them I know would have a desire to get back in here. We've got to make sure we are part of that plan by giving them the direction that they need."

The front row was the other positional group that Foster said the All Blacks selectors had trouble with. Having lost Joe Moody to a season-ending knee injury, the selectors have called upon the uncapped Chiefs loosehead Aidan Ross to fill the void.

Foster was excited by the talent emerging in the propping stocks, but indicated that the selections of George Bower and Ross forced the selectors to factor in experience when picking their loosehead option.

It's for that reason that Karl Tu'inukuafe was included at the expense of promising youngster Ethan de Groot, despite the former's imminent defection to French club rugby.

"There is a young group coming through which we are pretty excited about. Ireland are a very, very strong team, strong set-piece team," he said.

"If you look at our looseheads with George and Aidan, very consistent scrummagers, very reliable in that space but relatively new at the international level and that swung it around for Karl Tu'inukuafe's selection.

"He is our strongest loosehead scrummager and we think for right now, he's the best way to support the other two front rowers."

De Groot was the unluckiest omission at prop after making his All Blacks debut last year and impressing in Super Rugby Pacific with his consistent performances around the park.

Foster said that, in the end, the loosehead selections came down to strength at scrum time and off-the-ball work rate around the park.

"When it came to looseheads, we've been really impressed with George Bower, we believe that Aidan Ross has gone up a couple of cogs again at scrum time, and we know that Karl is our number one loosehead scrummager," he said.

"So, in that particular aspect, he will bring experience to those other two. With Ethan, we think he can get fitter, we think there is more to him, getting up off the ground and getting involved.

"We've got a really high regard for him and we'll put a plan in place to give him an opportunity to come back."

Foster hoped that the squad's six uncapped players - Fakatava, Ross, Roger Tuivasa-Sheck, Leicester Fainga'anuku and Stephen Perofeta - would light the fire under established squad members to bring more out of them as they prepare for their toughest home series since the 2017 British & Irish Lions tour.

"It's a squad with enough of an eye on the future for what we are looking at," Foster said.

"Six new players, there is a little bit of pragmatism about it getting the balance between giving the new players the best opportunity to play with a bit of experience around them.

"It's pretty simple - you've got to win now and win later. Everything that we do is with that in mind, but our job is to pick for the now and the future at the same time. In our mind, we've got a nice balance in that space.

"Sometimes it's a matter of relying on a new energy to bring out a little bit more from the players that have been there a little while.

"There's a test for a few, these next three-to-four months are going to be vital for some players to keep making sure they are making the gains and progressing because there is still two more squads to be named."