Trent passed away at a hospital in Menorca on Saturday (March 21) after a long illness, according to her website. Further details of her passing weren't provided.
Trent reportedly scored her first recording contract in the early 1960s and topped the charts in 1965 with "Where Are You Now (My Love)."
She and her ex-husband Tony Hatch collaborated on writing more than 400 songs, including material for Shirley Bassey, Jack Jones, Nancy Wilson, Des O'Connor, Val Doonican, Vikki Carr and Dean Martin, the BBC reports.
The couple also wrote the theme song for the long-running Australian TV drama Neighbours in the early 1980s. They divorced in 2002, and she Trent married Colin Gregory three later.
Trent returned to the stage later in life, touring the U.K. in the musical High Society and playing a series of concerts in 2004, the BBC says. A musical about her life, which is based on an as-yet unpublished autobiography, is set to open in May.
Trent is survived by her husband, Gregory, and her children Michelle and Darren.