As a Labor MP since 1981, Helen Clark has held important positions in the NZLP and the New Zealand government. During her 19 years in Parliament, her unofficial title was "Mother of the House," reflecting her role as the longestserving woman member among the then-current members of the New Zealand Parliament.
In 1984 she was chair of the ad hoc Disarmament and Arms Control Committee and Foreign Affairs and Defense Committee. She was also a member of the Government Administration Select Committee. She was the convener of the Government Caucus Committee on External Affairs and Security from 1984–87. In 1986 she was awarded the annual Peace Prize of the Danish Peace Foundation for her work in promoting international peace and disarmament.
From August 1987 until January 1989 Clark was minister of conservation, and was minister of housing from August 1987 until August 1989. In 1989–90 Clark was minister of labor and minister of health. While minister of health, she introduced tobacco-control legislation designed to provide protection against second-hand smoke in workplaces and public places, and to eliminate tobacco advertising and tobacco-company sponsorship of sporting events.
She was the first New Zealand woman to hold the cabinet-level position of deputy prime minister (1989–90); while in this post, she chaired the Cabinet Social Equity Committee and was a member of the Cabinet Policy Committee, Cabinet Committee on Chief Executives, Cabinet Economic Development and Employment Committee, Cabinet Expenditure Review Committee, Cabinet Honors Appointments and Travel Committee, and Cabinet Domestic and External Security Committee.
Clark became the first New Zealand woman privy counselor upon her appointment to the Privy Counsel in 1990. After a term as deputy leader of the opposition (1990–93), she became leader of the opposition in December 1993. She led the opposition until 1999 when she was elected prime minister on 27 November 1999. She is also minister for arts, culture, and heritage and minister in charge of the New Zealand Security Intelligence Service.
In July 2002, Clark's NZLP won the right to continue to lead the government for another three-year term. The elections were remarkable for the weak showing by the conservative National Party, which garnered just 21% of the vote, about half of the votes received by NZLP. It was the worst showing for the National Party in New Zealand election history. The new voting system initiated in 1996 was viewed as eroding the dominance of the two parties —Labor and National—that had existed throughout the country's history. Smaller parties experienced significant growth under the new system in 2002. NZ First, campaigning on an a platform to pare back immigration, won about 10 percent of the vote, placing third. The government coalition included the Greens, which placed sixth, winning eight seats in Parliament.