The Junior World Championship campaign will kick-off on Friday 10th June with a clash against Argentina (17.10, S4C).
Carmarthen Quins and Scarlets Academy centre Rheon James joined Bridgend wing Ross Jones as late replacements after Blues wing Harry Robinson and centre Adam Warren were ruled with ankle ligament and hamstring injuries respectively.
James was capped for Wales Under 20 during the recent Under 20 Six Nations and started for the Scarlets against Saracens in January in the LV= Cup.
Bangor-born Iolo Evans and Llanelli's Dale Ford are amongst the new caps in the squad.
Wales coach Webster said: "The Argentina game is massive for us and will go a long way to determining how we do in the tournament. I'm sure they'll have a big pack mentality which we will need to front up to that and then hopefully move them about a bit."
Webster added, "New Zealand have never lost a Junior World Championship game so we will have it all to do. That said, we will do our utmost to cause an upset or at least get something out of the game in order to have a good chance of reaching the last four.
"The Junior World Championship is an intense competition with five matches in 16 days and it will give the players a great insight into what it takes to become a professional rugby player. It's going to be tough but we have a good mix of talent throughout the squad, and we will make sure we fly the Welsh flag with pride."
Wales' Junior World Championship squad:
Backs:Liam Williams (Llanelli), Ross Jones (Ospreys / Bridgend), Eli Walker (Ospreys / Swansea), Dale Ford (Scarlets/ Llanelli), Owen Williams (Blues / Cardiff), Rheon James (Scarlets / Carmarthen Quins), Iolo Evans (Scarlets/ Llanelli) Steve Shingler (London Irish), Matthew Morgan (Ospreys / Swansea), Lewis Robling (Dragons/ Newport), Lewis Jones (Blues/ Pontypridd), Jonathan Evans (Dragons / Newport)
Forwards: Rhodri Jones (Scarlets / Llanelli), Lewis Smout (Blues / Pontypridd), Will Taylor (Ospreys / Swansea), WillGriff John (Blues / Pontypridd), Kirby Myhill (Scarlets / Llanelli), Sam Parry (Llandovery), Cory Hill (Blues / Pontypridd), Macauley Cook (Blues / Cardiff), Luke Hamilton (Blues / Glamorgan Wanderers), Lloyd Peers (Ospreys / Bridgend), Edward Siggery (Pontypridd), Thomas Young (Blues / Cardiff), Ben Thomas (Ospreys / Bridgend), Owen Sheppeard (Blues / Pontypridd)
Watch Wales U20 in action (UK time):
Wales v Argentina, Friday 10 June, 17.10 (Padua)
Wales v New Zealand, Tuesday 14 June, 17.10 (Rovigo)
Wales v Italy Saturday 18 June, 17.10 (Treviso)