Kirk was Deputy Opposition Whip in the Senate, the Deputy Chair of the Foreign Affairs sub-committee of the Joint Standing Committee on Foreign Affairs, Defence and Trade (JSCFADT), a member of the Human Rights sub-committee of JSCFADT and a long-standing member of the Senate Legal and Constitutional Committee.

Her policy interests focus on legal and constitutional issues, foreign affairs and international relations, refugees and migration, human rights, and the protection of women and children.

She was the Convenor of Parliamentarians Against Child Abuse and a former Deputy Chair of the Status of Women Committee of the Federal Caucus.

Kirk served only one term in the Senate after being defeated for Labor Party preselection by Don Farrell ahead of the 2007 federal election.

[2] It marked a role reversal from six years earlier, when she defeated incumbent Senator Chris Schacht for preselection.