Kate Lundy and Andrew Leigh would have backed Julia Gillard in Thursday's leadership ballot.
Senator Lundy was the first ACT Labor MP to declare her stand.
‘‘@JuliaGillard has my full confidence and ongoing support,’’ the Multicultural and Sports Minister tweeted, just minutes after Ms Gillard told Parliament the leadership ballot would be held at 4.30pm.
Member for Fraser Andrew Leigh told The Canberra Times he would vote for Ms Gillard.
Member for Canberra Gai Brodtmann has not publicly declared her hand and insisted she would not comment before the caucus ballot.
But sources close to her in the NSW Right say Ms Brodtmann would have supported Kevin Rudd, who did not stand in the ballot.
The Member for Canberra did not confirm or deny it when it was put to her by The Canberra Times.
In last year’s leadership challenge Ms Brodtmann voted for Ms Gillard.
Across the NSW border, Minister for Defence Materiel Mike Kelly has also so far not returned calls to The Canberra Times to state where his support lay.
ACT Chief Minister Katy Gallagher declined to take sides.
“This is a matter entirely up to the federal Labor party. There is no doubt the ongoing leadership speculation has been bad for the government and the party and it needs to be resolved once and for all,” she said.