On 14 August 2017, Joyce became embroiled in the 2017 Australian parliamentary eligibility crisis, announcing to the House of Representatives that he had received advice from the New Zealand High Commission that he could possibly hold New Zealand citizenship by descent from his father. Joyce asked the government to have him referred to the High Court in the Court of Disputed Returns for consideration and clarification of his eligibility alongside that of Senators Ludlam, Waters, Canavan and Roberts. Later in the day, the New Zealand Department of Internal Affairs and the Crown Law Office confirmed that Joyce was indeed a New Zealand citizen. He quickly renounced his New Zealand citizenship. On 27 October 2017, the High Court ruled that Joyce had been ineligible to be a candidate for the House of Representatives at the time of the 2016 election, since he had been a dual citizen at that time, and that his election was therefore invalid. The ruling cast doubt on the validity of ministerial decisions made after August 2017.