Katherine O'Regan (
24 May 1946 - ) is a former
New Zealand politician. She was an MP from
1984 to
1999, representing the
National Party. She was first elected to Parliament in the
1984 elections as MP for
Waipa, replacing the retiring
Marilyn Waring. She had served as Waring's personal assistant since
1975. She held the seat of Waipa until it was abolished in the
1996 elections. She then unsuccessfully contested the seat of
Tauranga against
Winston Peters, but remained in Parliament as a
list MP. In the
1999 elections, she again challenged Peters, and came within a hundred votes of defeating him — had she won, the
New Zealand First party would have lost all parliamentary representation. Unlike in 1996, O'Regan was not high enough on National's
party list to remain in Parliament without winning an electorate. She has not return to Parliament since then.