New Zealand mid-court dynamo Temepara George has announced her retirement from international netball ahead of a series against Australia.

Regular captain and ace defender Casey Williams is also unavailable, out for the remainder of the year as she recovers from ankle surgery.

Their absence from the squad named on Monday for the upcoming series against world champions Australia was offset by the inclusion of two newcomers in Kayla Cullen and Julianna Naoupu.

Coach Ruth Aitken hailed vice-captain George, an 89-Test veteran, as an outstanding athlete and important part of the Silver Ferns for more than 10 years.

"We are very sad to see her go but wish her all the very best as she moves on with the next stages of her life," she said.

The selectors named Northern Mystics 19-year-old Cullen and Waikato-Bay of Plenty's Naoupu, 21, in the Silver Ferns squad for the first time.

Aitken said their inclusion highlighted the value of the trans-Tasman league as young players were now getting greater opportunities which helping to build player depth.

"Both Kayla and Julianna have had strong ANZ Championship seasons and have continued their form with the New Zealand under-21 team," she said.

"Looking towards the next four-year cycle it is now time to give these young players an opportunity to take their game to the next level and grow a core of players that will progress through to the next world championship."

Silver Ferns squad: Leana de Bruin, Kayla Cullen, Katrina Grant, Paula Griffin, Joline Henry, Laura Langman, Cathrine Latu, Camilla Lees, Liana Leota, Julianna Naoupu, Grace Rasmussen, Anna Scarlett, Anna Thompson, Maria Tutaia, Irene van Dyk.