She previously had a long history involved in New Zealand Unions, having served as the president of the Association of Staff in Tertiary Education and was heavily involved in the Council of Trade Unions (CTU) Women's Council Convenor and attended the ICFTU World Women's Conference as one of two CTU delegates.
Ovens was an Alliance candidate in Auckland's Mount Albert electorate in the 1999 and the 2002 elections, both times contesting the seat against Labour leader Helen Clark. On the party list, she was ranked 28th and 12th, respectively. Ovens became president of the Alliance party in 2004. She had previously been critical of the party's leader, Matt McCarten, for his close associations with the Māori Party. For the 2005 election she unsuccessfully contested the Manukau East electorate and was ranked first on the party list, having been elected a co-leader with Paul Piesse.
In 2006 she resigned as co-leader and left the Alliance party. After being elected the northern secretary of the Service & Food Workers Union in succession to Darien Fenton, she decided to join the Labour Party as it is affiliated with the Union.
Since her election to the SFWU Ovens has been occasionally blogging on left wing social media websites and supporting union activities primarily based in Auckland. In December 2014 Ovens helped lead a walkout of food service workers at Auckland City Hospital.
- "Archived copy". Archived from the original on 6 February 2006. Retrieved 6 August 2006.
- Young, Audrey (6 August 2006). "Ovens switches to Labour after winning union vote". The New Zealand Herald. Retrieved 11 April 2017.
- "Auckland Hospital workers walk over outsource call". Stuff.co.nz. 15 December 2014. Retrieved 8 April 2017.
- "GUEST BLOG: Jill Ovens – Auckland Hospital worker cuts – Democracy the loser « The Daily Blog". Thedailyblog.co.nz. 17 December 2014. Retrieved 8 April 2017.