Rt Rev Brian Patrick Ashby (10 November 1923-5 June 1988) served as the fifth Roman Catholic Bishop of Christchurch from 1964 until his resignation in 1985. Born in the Christchurch suburb of Belfast, he earned a B.A. from the University of Canterbury before entering Holy Cross College, Mosgiel, to prepare for the priesthood. He completed further theological studies and was ordained in Rome on 1 January 1950, later earning a doctorate in theology in 1951.

Ashby was consecrated bishop on 5 August 1964, just as the Second Vatican Council was underway. He played a leading role in implementing Council reforms in New Zealand—overseeing liturgical changes, sanctuary redesigns, and the construction of Our Lady of Victories Church in 1968. A committed advocate of social justice, he addressed issues such as Māori–Pākehā relations and opposed apartheid, notably supporting the anti-apartheid movement during the 1981 Springbok rugby tour.

In 1983, Pope John Paul II appointed him to the Vatican Secretariat for the Promotion of Christian Unity, and he became the first New Zealand Catholic bishop to serve on the Anglican–Roman Catholic International Commission (ARCIC II). That same year he was appointed CBE in recognition of his service.

Visible and accessible, Bishop Ashby also co-directed the New Zealand Catholic Enquiry Centre before his consecration. After suffering a stroke, he resigned in 1985 and later became President of the NZ Counter-Stroke Support Group. Diagnosed with terminal cancer in early 1988, he passed away on 5 June that year.