Bishop Moran died in Dunedin, May 1895, and was succeeded by Michael Verdon, of the archdiocese of Dublin. Canon Verdon was a nephew of Cardinal Cullen, of Dublin, and a cousin of Cardinal Moran, of Sydney. Before coming to New Zealand he had been on the staff of Clonliffe College (Dublin Diocesan Seminary), Vice-Rector of the Irish College, Rome, and first Rector of Manly College, Sydney. He undertook the founding of the National Seminary at Mosgiel in 1900, and was its first president. Until 1934 the seminary professors were chosen from diocesan priests of New Zealand, Australia, and Ireland. Priests of the Congregation of the Missions (Vincentians) from Australia took charge of the National Major Seminary in 1934.

On the death of Bishop Verdon, in 1918, James Whyte, of the archdiocese of Sydney, was appointed to Dunedin. In 1942 he asked for a coadjutor, and Hugh J. O'Neill, of the diocese of Dunedin, was nominated and consecrated in 1943. A sudden decline in health caused Bishop O'Neill to resign (died 1955), and John P. Kavanagh, of the archdiocese of Wellington, was consecrated as coadjutor. On the death of Bishop Whyte, in 1957, Bishop Kavanagh succeeded to the see.