She is one of the four co-authors of the poetry collection Millionaire’s Shortbread (2003). Mike Houlahan remarks that Duffy’s poems ‘use cultural events for reflections that can be wry and fantastical.’ She has had writing published in the journal Sport, and has also written for Booknotes. Mary-Jane Duffy is involved with the Mary Newton Gallery in Wellington, which promotes the work of contemporary artists.