At the beginning of his second term as an MP, Ririnui was appointed a Parliamentary Under-Secretary to the ministers responsible for Conservation, Corrections and Treaty of Waitangi Negotiations; in July 2004, his Conservation portfolio was replaced with Health. In December 2004 Ririnui instead became a Minister outside Cabinet, as a Minister of State with Associate Ministerial roles in the Corrections, Health, Treaty of Waitangi Negotiations, and Forestry portfolios, and held these roles until the defeat of the Labour government in 2008. He also chaired the Labour Party's internal Maori Caucus.