Harbour Nocturne was the first of four Wellington pieces that Pruden planned to compose on his return from England in the mid-1950s and it is arguably his most popular work. It was completed and played at the 1956 Cambridge Summer School, and the National Orchestra (now the NZSO) gave a studio broadcast performance under Alex Lindsay on 17 November 1959. The first public performance was given at a subscription concert by the Alex Lindsay Sting Orchestra in the Wellington Town Hall Concert Chamber on 4 December 1961, and the second was by the National Orchestra conducted by Pruden at a Summer Proms concert in the Wellington Town Hall on 14 February 1963.

Harbour Nocturne is an impressionist tone poem that depicts the Wellington waterfront at nightfall. Pruden suggested that it had a literary parallel in the opening paragraphs of Katherine Mansfield's short story The Voyage (1921), which describes the Picton boat's nighttime departure from Wellington, with people bidding farewell to their loved ones on board and the wharf lamps dispersing a "quivering light in all that blackness". Musically, the piece owes something to Copland's night scenes on the ranch and to the meditative sea interludes in Britten's Peter Grimes. The work was first recorded commercially by an expanded Alex Lindsay String Orchestra and this recording was played on Robert Burch's boat when Pruden's ashes were scattered on Wellington harbour following his death on 1 October 1982.