Patrick Joseph O'Regan (6 February 1869 – 24 April 1947) was a Member of Parliament for Inangahua and Buller, in the South Island of New Zealand.

[1] He was involved with the Knights of Labour and Henry George's Single Tax Movement.

In 1896, O'Regan introduced the Proportional Representation Bill into Parliament: it failed to carry the second reading by only 6 votes.

[2] A lawyer by profession, O'Regan represented striking workers in 1913 and conscientious objectors charged with sedition in World War I. O'Regan supported Labour's Peter Fraser in the 1918 by-election in Wellington Central and Harry Holland in the 1918 by-election in Wellington North.

[3] O'Regan was made a judge of the Court of Arbitration in 1937 and a member of the Legislative Council on 9 September 1946 and he held that position for the few months until his death in Wellington on 24 April 1947.