She has joined a ginger group within the party that is uncomfortable with Australia holding people indefinitely in detention camps.

Senator Gallagher was speaking after a Palm Sunday rally in Civic attended by several thousand people.

"I am uncomfortable with what is going on now, that's where I'm at," she told Fairfax Media.

"I don't always agree with everything in the Labor Party does … I'm of the group that is advocating for change.

"You are in a political party to influence policy and you influence policy through your national conference, that's the chief decision-making body so I would expect this would be discussed, I don't know to what extent and what the outcome would be."

Senator Gallagher wore an "ACT Labor for refugees" tee as she listened to former ACT Chief Minister Jon Stanhope blast the ALP as well as the Coalition over the issue.

He said Australia had abrogated its responsibility to international treaties it had signed.

"More importantly perhaps even than the breaching of international accords, we have in our treatment of asylum seekers including children acted in ways that are not consistent with core Australian and human values of compassion, generosity, fairness, freedom, equality and common humanity," he told the crowd.

"Australia has been found by the United Nations to be a country that has, through its asylum seeker policy, facilitated torture.

"In this contest, the furious race to the bottom, the ALP jettisoned the principled position on asylum seekers outlined in its national platform.

"It's time to demand that the Labor Party return to the principles outlined in the national platform including its stated total opposition to mandatory and indefinite detention and that the Labor Party construct policies consistent with the beliefs and the values which it boasts that it holds.

"It's time that all Canberrans demanded publicly and privately of all of our four local members and senators, that they stand up for the principles and policies that we elected them to represent and that we expect them to support."

Mr Stanhope was the administrator of Christmas Island where many asylum seekers were held after arriving on boats.

Senator Gallagher said that role gave Mr Stanhope a particular insight into the complex issue.

"His understanding of the issue is second to none in the country, he'd be one of the handful of people who have seen it first hand," she said.

Senator Gallagher said she agreed with Mr Stanhope's statement that Australia was breaching its obligations under international treaties.

"I don't really disagree very much with whatJon says," she said.

"There is a group within the Labor Party membership that is deeply uncomfortable about some aspects of the asylum seeker policy and not just the policy but the way the debate is conducted in Australia.

"Part of my being here [at the rally] is to support other Labor Party people, we can advocate for change within the party.

"It's not easy and the political climate makes those discussions difficult particularly when anyone speaking out is immediately portrayed as someone who is anti-Australian or anti-national security.

"But I don't think you would find many Australians who, if they fully understood what was going on in detention centres and offshore processing, would be that comfortable with how it is being conducted and the costs and the unwillingness to look at other alternatives."

The rally was also addressed by Ismail Hussaini who fled from Pakistan alone at the age of 17 and undertook the boat journey from Indonesia to Australia.

After being stopped at Ashmore Reef, he spent time at the Christmas Island and Darwin detention centres before being released into the community.

He is now a journalism and communications student at the University of Canberra.