New Zealand's 34-10 semi-final win over Tonga on Saturday set up a World Cup final against Australia at Suncorp Stadium next Sunday.
The result sends five Panthers to the decider: Isaah Yeo and Liam Martin with the Kangaroos, and Casey McLean, Moses Leota and Isaiah Papali'i with the Kiwis.
In wild conditions in Newcastle, New Zealand trailed 10-6 before taking a 12-10 lead into halftime.
McLean's individual effort in the 48th minute extended the advantage, and the Kiwis kept Tonga scoreless in the second half.
Tonga's defeat ended Paul Alamoti's tournament.
Australia secured its final place with a 44-12 win over Samoa on Sunday at Allianz Stadium, in front of 41,259 fans.
Yeo and Martin's Kangaroos scored five first-half tries to lead 26-2 at the break.
Brian To'o and Izack Tago's Samoa faced a difficult second half. Tago finished a sweeping move in the 61st minute to cut the score to 32-12.
Australia added two more tries, ending Samoa's bid for a second consecutive appearance in the final.