Matenga was born in Rarotonga.[3] After playing senior tennis as a teenager, she moved to Auckland, New Zealand in 1973 to pursue a professional tennis career.[1][3][4] In 1974 she moved to Wellington, where she joined a local Pacific Islands Church netball team.[5] In 1975 she trialed for the Silver Ferns and was selected for the 1975 World Netball Championships as a reserve. In 1978 she was selected for the team, becoming the first Pacific Islander to play for the Silver Ferns.[1] She subsequently competed in three World Netball Tournaments,[1] as well as the 1985 World Games.[3] During the 1980s, Matenga formed a notable shooting partnership with fellow Silver Fern Margaret Forsyth, known together as the "two Margs".[5]