New Zealand had a set-piece clinic from South Africa last year, and so the size and techniques of the tight five are under the microscope.
Robertson and his assistants Leon MacDonald (attack) and Tana Umaga (defence) will name the 28-man squad for the Junior World Championship after the Oceania tournament.
Some Super Rugby players may come into contention, notably the Blues trio of loose forwards Blake Gibson and Akira Ioane, and wing Tevita Li, scorer of six tries in the 2014 JWC. All three are on the fringes of the Blues top starting line-up, but should be released as the franchise will not be involved in the playoffs.
Crusaders outside back Nathaniel Apa may also be available to travel to Italy. Damian McKenzie will be staying with the Chiefs to cover for injured Aaron Cruden, denying the Under-20s a prime attacking threat. But they do have talent aplenty in the backline.
While there will be some rotation for the Oceania tournament, Robertson is not viewing this event as three trial matches, not after the exhaustive selection process and training camps.
"We're not trialling. We're going to perform, and if you perform, you have an opportunity to go away to Italy. There is a winner of the [Oceania] competition, so we have to balance performance development and results," he said.
Waikato prop Atu Moli, one of eight survivors from the 2014 side that placed third, is expected to be named skipper.
The squad flies to Australia on Tuesday and faces Japan next Friday, Samoa on May 5 and Australia on May 9.