Selleck is a composer, flautist and writer. She teaches at Melbourne University and the Victorian College of the Arts, works at the Centre for Studies in Australian Music and is currently completing a PhD in composition. She has composed a wide range of chamber, orchestral and electronic works. Her works have been performed by the Queensland, Tasmanian and Melbourne Symphony orchestras. She performed the solo part of her flute concerto Unspoken Dialogues with the Melbourne Symphony in a recording at the Iwaki Auditorium in 2003.
Commissions have included works for Ensemble Zauberflöte, Melbourne Grammar, Melbourne University, the Cairnmillar Institute, Melbourne Youth Music, Astra and the Port Fairy Spring Festival. Her first opera, The Quickening, received its premiere at the Port Fairy Festival in October 1998 and was published by the Centre for Studies in Australian Music in 2001. Her piano quartet Looking Back was selected for performance at Maltese Australian Culture Week in Malta in January 2004.
In 1990 Selleck was awarded the Percy Grainger Prize for Composition and in 2006 she was awarded First Prize in the 2006 Albert H. Maggs Composition Award.