When the Whitlam government won office at the December 1972 election, Wriedt (associated with the ALP's right wing) became Minister for Primary Industry. In June 1974 his portfolio was renamed Agriculture. On 14 October 1975, Rex Connor was obliged to resign as Minister for Minerals and Energy, as a result of the Loans Affair, and Wriedt was appointed in his place. Nevertheless, he served less than a month before the Whitlam government was dismissed on 11 November. Wriedt remained in the Senate until his resignation in September 1980 to contest the House of Representatives seat of Denison at the 1980 federal election; he was defeated by sitting Liberal MP Michael Hodgman.