Viliami Ma’asi is an international Tongan rugby union player who plays as a hooker. He spent his entire professional career in England and finished his career in National League One (the third division) with the Ampthill club.

Viliami Ma’asi made his first appearance for the Tonga national team on November 16, 1997, against the Wales team.

He was selected to participate in the 2003 Rugby World Cup in Australia, sharing the hooker position with Ephraim Taukafa. During the competition, he played in four matches, including two as a starter.