The advent of MMP in New Zealand parliamentary politics in the 1990s — culminating in the use of the new electoral system from 1996 onwards — led to a series of defections and re-alignments as the old monolithic two-party system broke up and many politicians struggled to define and project their images and beliefs in new parties and groupings. The new political climate tended to favour the foundation of political parties (whereas in former times dissidents had often simply became independent MPs). Voters tended to punish many waka-jumpers in this period, but some survived and flourished, often to the disgust of their former party colleagues. Due to the frequency of waka-jumping in national politics, New Zealand enacted legislation (the Electoral Integrity Act of 2001, since expired) which required politicians elected from a party list to resign from Parliament if they left their party's parliamentary caucus. As the actions of the Progressive Party in 2002 showed, parties can still find ways around such law.
In 2003 allegations against the ACT party MP Donna Awatere Huata emerged, eventually resulting in her arrest for fraud. As ACT had a reputation for vociferously attacking any perceived dishonesty by members of other parties, the charges against Awatere Huata occasioned considerable embarrassment. Awatere Huata refused to resign from Parliament, but the ACT caucus expelled her. That November the party itself removed her from its membership, and she became an Independent MP. ACT tried to remove her from Parliament by invoking the Electoral Integrity Act, as her departure from the party left ACT with fewer seats than the public had chosen to give it at the 2002 election. Awatere Huata, however, claimed that even if not a member of ACT, she still voted according to ACT policies, ensuring that the public still got the policies that they voted for. In a long battle, Awatere Huata sought a court injunction against the invocation of the Electoral Integrity Act. The High Court initially refused an injunction, but the Court of Appeal overruled that stance. Finally, on 18 November 2004, the Supreme Court unanimously upheld the original decision, allowing the invocation of the law. The following day, the Speaker declared Awatere-Huata's seat vacant, and the next person on the ACT list, Kenneth Wang, entered Parliament in her place.