The 21-year-old has been called up to replace Batley's Gareth Moore, who has withdrawn with a shoulder injury.
A statement issued by team management confirmed Scotland were granted permission to make the change to their 24-man squad by tournament organiser RLWC2013.
The summons caps a fine first year in the semi-professional game for Phillips after he was picked up from the Cumbrian amateur scene.
Phillips, who will join older brother Brett in the squad, said: "I got the call on Saturday morning to come down to training on Sunday as a few things were happening.
"When I got in the meeting before training I was told Gareth Moore had dropped out and I was in the squad. I was delighted but very nervous.
"This time last year I was playing for Seaton against Maryport in the Cumberland League - now I'm going to be in the World Cup with players like Danny Brough and NRL and other Super League players."
Phillips' call-up alongside Brett means that Scotland will again have two sets of siblings in their squad, along with Ian and Andrew Henderson.
The Scots did also have Hull KR brothers Jonathan and Adam Walker but the former pulled out with a knee injury.
Coach Steve McCormack is yet to confirm a replacement for Walker, although Whitehaven's former Castleford prop Paul Jackson is in the frame.