Why Ethan de Groot was left out of the All Blacks squad for third straight Test

Loosehead prop Ethan de Groot's omission from the All Blacks team sheet for a third consecutive week was one of the features of Scott Robertson's game day squad to face France on Sunday.

Days out from the Test against England, the Highlanders prop - who had embedded himself as the incumbent loosehead - was deemed unavailable due to a breach of "internal standards".

He was then left out of the group to face Ireland last weekend, and has suffered the same fate this week for their showdown with the hosts in Paris, with Robertson choosing to roll with Tamaiti Williams in the starting role and Ofa Tu'ungafasi off the bench.

It prompted speculation over whether the disciplinary breach was more severe than initially thought, or if it's simply a case of having been usurped in the pecking order.

Speaking from Paris on Friday, Robertson provided some clarity to the situation, confirming Williams and Tu'ungafasi had been too outstanding to leave out, having taken and sprinted away with their opportunities in both London and Twickenham.

"It's difficult not to play Ethan de Groot but the other two are playing great footy. It's as simple as that," said Robertson.

During the week, forwards coach Jason Ryan described the front-row selection as "probably one of the toughest" he's had in his career to date, such is the nature of the form and competition within the squad.

Starter Tyrel Lomax has been a rock throughout the northern tour, while newcomer Pasilio Tosi has made his mark with some powerhouse performances off the bench. Against Ireland, Asafo Aumua hit his stride in his spot start for Codie Taylor, who was ruled out due to concussion protocols.

Robertson echoed Ryan's sentiments that De Groot had responded impressively from his indiscretion on the training paddock.

"Ethan's done everything he can and he's been exceptional off the field under the situation he's in," he added.

"We've rewarded performance."