Zerefos was born in Australia of Greek parents, Paul and Katina. Her career was launched in 1961, at a time when musical variety shows were popular on television. She was the first person of Greek heritage to be a regular artist on Australian television.
She was a regular member of the Revue 20 headed by Claire Poole. This was a twenty-piece choral ensemble which provided background choruses for Seven Network variety programs such (Digby Wolfe's) Revue '61 and '62), (John Laws') Startime and Studio A hosted firstly by The LeGarde Twins and then by Colin Croft as well as Curtain Call, a late night variety program hosted by Revue 20 member John Wickham-Hall. She played Tuptim in a professional tent production of The King and I and Marion Paroo in The Music Man in January 1966 at Warringah Mall in Brookvale, on Sydney's Northern Beaches. She was also engaged to play Maria in a later production of The Sound of Music along with June Bronhill (Maria in the original Australian tour of the musical) who was to play the Mother Abbess. The project was scheduled to present six musicals, however only three (The King and I, Annie Get Your Gun and The Music Man) were actually produced. The project was abandoned for lack of both audience support and a dwindling capital base. The remaining musicals (Gypsy, Bye Bye Birdie and The Sound of Music) remained unpresented.
Zerefos was encouraged to pursue a career in America but her marriage in 1971 and strong family ties kept her in Australia.
Zerefos is also a tireless charity worker for the Aging Research Centre at Sydney’s Prince of Wales Hospital. Her father died suddenly in 1981 and her mother never recovered from that shock and soon began to show signs of Alzheimer's disease. Her mother needed constant attention, so Zerefos became her primary carer and she was soon fund-raising to assist research into this illness. Zerefos' husband, Raymond, died in 2002 after a lengthy, debilitating illness.
Her extravagant costumes earned her the nickname Helen Fairy Floss. She also made a number of LP recordings.