"With Stephen and Jordie not available, we needed extra cover at first-five-eight.
Ciarahn's time with the Chiefs Under 20 squad has gone well and he proved himself with the New Zealand Secondary Schools team last year. This is a good opportunity for him and one I am sure he will make the most of.
"We had hoped that Stephen would be available for selection. However, it's become clear he won't be ready in time for the tournament due to his ankle injury.
"As has been the case in previous years, players have been deemed unavailable for the Oceania tournament due to their Super Rugby commitments. No final decision on their availability for the World Championship in Georgia in May and June has been made."
The squad will travel to the Gold Coast for matches against Fiji on April 28, Samoa on May 2, and Australia on May 6. All matches will be played at Bond University.
Australian coach Simon Cron has selected a squad of 29 that will face Samoa, Fiji and New Zealand with one eye on the World Rugby U20s Championship in Georgia this June.
Players currently unavailable for selection due to Super Rugby or Australian Sevens commitments include Sham Vui (Western Force), Jordan Uelese (Melbourne Rebels), Esei Haangana (Melbourne Rebels), Izaia Perese (Queensland Reds), Sione Tuipulotu (Melbourne Rebels), Liam McNamara (Aussie 7s), Henry Hutchison (Aussie 7s), Simon Kennewell (Aussie 7s) and Lachlan Anderson (Aussie 7s).
Australia will be looking to win the Oceania championship for the first time, having competed in the tournament since 2015. In 2016, Australia defeated New Zealand in a tight match to level the series at 1-1; the first-time Australia had defeated New Zealand at U20s level.
"We had a very short national camp last week and have coached some of the basic areas we need to do well to be successful. As a squad we had a chance to work on some cohesiveness in our ball skills and talk about key fundamentals around which we will base our attack and defensive systems," says Cron.
"We'll head into camp on the Gold Coast next Tuesday and we need to continue on from where we left off. We have to keep building on the boys' rugby brains as well as the tactical and technical coaching. There are some great boys in the group and I am looking forward to working with them more in detail over the coming weeks."
The Australian squad is subject to change depending on Super Rugby requirements leading into the tournament.
New Zealand Under 20s to Australia:
Forwards: Asafo Aumua (Wellington), JP Sauni (Auckland), Pouri Rakete-Stones (Hawke's Bay), Alex Fidow (Wellington), Ezekiel Lindenmuth (Auckland), Harrison Allan (Canterbury), Sam Caird (Waikato), Jacob Pierce (Auckland), Isaia Walker-Leawere (Wellington), Sam Slade (Auckland), Luke Jacobson (Waikato, c), Tom Christie (Canterbury), Adrian Choat (Auckland), Marino Mikaele-Tu'u (Hawke's Bay), Dalton Papali'i (Auckland), Ryan Coxon (Waikato), Tim Farrell (Hawke's Bay)
Backs: Kemara Hauiti-Parapara, Carlos Price (Wellington), Ere Enari (Canterbury, vc),
Ciarahn Matoe (Taranaki), Josh McKay (Canterbury), Tiaan Falcon (Hawke's Bay), Orbyn Leger (Counties Manukau), Thomas Umaga-Jensen (Wellington), Braydon Ennor (Canterbury), Tamati Tua (Northland), Tima Faingaanuuku (Tasman), Caleb Clarke (Auckland), Will Jordan (Canterbury), Jona Nareki (Otago)
Australian Under 20s for Oceania series:
Props: Harry Johnson-Holmes (NSW), Harry Chapman (NSW), Va'auli Fa'amausili (Victoria), Dan Matthew (NSW)
Hookers: Tom Horton (NSW), Efi Ma'afu (Queensland), Sama Malolo (Western Australia)
Locks: Harry Hockings (Queensland), Angus Blyth (Queensland), Ryan McCauley (NSW),
Darcy Swain (ACT)
Loose forwards: Lachlan Swinton (NSW), Angus Scott-Young (Queensland), Reece Hewat (Queensland), Liam Wright (Queensland), Angus Allen (ACT)
Halfbacks: Harry Nucifora (Queensland), Ryan Lonergan (ACT), Theo Strang (NSW)
First fives: Hamish Stewart (Queensland), Jack McGregor (Victoria)
Midfielders: Tony Hunt (Queensland), Nick Jooste (ACT), Dylan Riley (Queensland), Len Ikitau (ACT)
Wings: James Ramm (NSW), Jayden Ngamanu (Queensland)
Fullbacks: Semisi Tupou (Victoria), Jack Maddocks (Victoria)