[1] His father was Patrick O'Regan, then a Member of Parliament and later a prominent Wellington judge[2] of the Arbitration Court.

[2] During World War II he served as a surgeon aboard three different hospital ships (the Maunganui, Oranje and Pacific Star) where he was largely responsible for the evacuation of wounded Allied servicemen from Burma.

He unsuccessfully lobbied for the government to intervene and cancel the tour alongside such figures as George Nēpia and Vincent Bevan.

[7] In 1974 was elected president of the Harbours Association at its annual conference, succeeding Sir Henry Blyde.

[8] O'Regan stood for election to the New Zealand House of Representatives for the Labour Party for the seat of Wellington Central in 1966 finishing runner-up.