Auckland centre Rieko Ioane has received a shock call-up to the All Blacks squad for Saturday's second Bledisloe Cup Test against the Wallabies.

The 19-year-old has joined the squad in Wellington, where coach Steve Hansen confirmed his inclusion as an injury replacement for second-five Ryan Crotty who suffered a head knock against Australia in Sydney.

Ioane will cover both the midfield and outside backs with winger Waisake Naholo ruled out with a hamstring injury.

Seta Tamanivalu, Liam Coltman, James Parsons and Damian McKenzie have also been called in, with Nathan Harris (knee), and Codie Taylor (head knock) also ruled out.

"He [Ioane] had a very good Super Rugby season and he's really someone we see in the future that could have a long career, he's only 19," Hansen said.