 Following the 1989 Origin series (and thanks to injuries to South Sydney's Mario Fenech and Balmain's Benny Elias), Trewhella was selected as a hooker in the 20 man squad for the mid-season 1989 Kangaroo Tour of New Zealand.He played in 3 of the 6 games on tour, but was not selected for any of the tests against New Zealand with coach Bob Fulton preferring Queensland and Brisbane Broncos rake Kerrod Walters in the role.Trewhella also played 2 games for Country Origin in 1988 and 1989.