Helen Patricia Duncan MNZM (7 November 1941 – 6 February 2007) was a New Zealand politician and a member of the Labour Party.

Duncan was born in Greymouth on the West Coast, and attended the University of Canterbury, the University of Auckland, and Christchurch Teachers' College. She worked as a teacher in a number of different cities including Lower Hutt, Masterton and Auckland. She was involved with the New Zealand Educational Institute (Te Riu Roa) and the New Zealand Council of Trade Unions.

She first stood for Parliament in the 1996 election, unsuccessfully in the Auckland electorate of Epsom for the Labour Party.^[2][3]

In 1998 Jill White, a Labour list MP, resigned from Parliament. As Duncan was the next-ranked person on the Labour Party list, she entered Parliament in White's place.

In the 1999 and the 2002 elections, Duncan remained in Parliament as a list MP, also unsuccessfully contesting the North Shore electorate.

She left Parliament at the 2005 election after being diagnosed with cancer. She died on 6 February 2007.^[1][4][5]

In the 2005 Queen's Birthday Honours, Duncan was appointed a Member of the New Zealand Order of Merit, for public services.^[1][6]