Following the success of this Red-Green Coalition in the 2005 parliamentary elections, the Centre Party entered the government, and Haga succeeded Erna Solberg as Minister for Local Municipalities and Regional Development in the second cabinet Stoltenberg. In September 2007, she became Minister of Petroleum and Energy, succeeding Odd Roger Enoksen, and leaving the regional department to Magnhild Meltveit Kleppa. On 11 April 2008, Haga announced that she would not be seeking re-election to Parliament at the 2009 election, and that she would step down as Centre Party leader before the election.