Kaino returns to NZ before Bledisloe Test

All Blacks flanker Jerome Kaino has flown home from Sydney to deal with a personal matter, New Zealand Rugby says.

Australian media reports of an extra-marital affair have triggered the return of the 81-Test veteran ahead of the first Bledisloe Cup Test on Saturday.

Kaino had not been selected in the All Blacks match-day squad, coach Steve Hansen opting instead for nine-Test Liam Squire to start as blindside flanker.

An NZR statement on Saturday confirmed that Kaino had returned "to deal with a personal matter following the publication of a story in the Australian media this morning".

The news comes just days after NZR re-opened its investigation into All Blacks halfback Aaron Smith's airport "toilet tryst" scandal.

The incident with a woman at Christchurch airport resulted in Smith being sent home from last year's tour of South Africa and subsequently suspended.

An NZR statement on Thursday said an independent lawyer would investigate the matter further, after reports Smith may have misled his All Blacks bosses over the incident.

Chief executive Steve Tew said on Saturday that information concerning Smith published in New Zealand media was also a new development.

"NZR cannot comment at this stage on what are both personal matters, but we feel for all of those affected," he said in a statement.

"We certainly understand that our game and our players are under public scrutiny and these latest stories are concerning."

NZR would not comment on individual behaviour, Tew said.

"But it is clear that this is really hurting rugby, all the people concerned, our fans and supporters," he said.

The review is being presented to the NZR board this month, and Tew said the organisation was looking to make it public sometime in September.