Senator Bridget McKenzie has accused Cathy McGowan of turning her back on the people who elected her as Indi MP, by voting to allow refugees get medical treatment.
Under the new bill, people on Nauru and Manus Island could be transferred to Australia in an emergency.
As the next federal election looms, Senator McKenzie has stepped up the battle with independents, saying it was disappointing that in her final months in Parliament, Ms McGowan "appears to be toeing the party line of the left-leaning Voices 4 Indi".
“It is clear today’s Voices 4 Indi movement is not the same as the one which first supported Cathy McGowan,” she said.
“What we have seen in Parliament is a highly-regarded, widely-respected, hard-working representative bowing to the whims of a left-leaning lobby group."
Ms McGowan would not address Ms McKenzie's criticism when asked to comment, but said she supported the medical transfer bill because it provided a balance between urgent medical treatment and national security.
“The message from the community is clear – an overwhelming majority of comments are in favour of the medical evacuation bill,” Ms McGowan said.
“I believe the amendments help ensure critically-ill people in our care have access to medical treatment."
The next V4I candidate Helen Haines said if she was in the Indi MP's seat, she would have also voted with the crossbench as the bill aligned with her personal beliefs and the majority of correspondence to Ms McGowan.
"Sometimes you have to take the mantle and be a leader and listen to what the people are saying, but understand that you can't keep everybody happy," she said.
"If you're hearing two sides of one story, you then need to apply all of the other components … What is the evidence telling you, what are your life experiences telling you, what are your values telling you about what is right?"
She said she believed she was brave, capable and willing enough to make the tough decisions.
“That’s really in contrast to being the delegate of a major party," Dr Haines said.
"If you’re the Liberal candidate or Nationals candidate or Green, you’re going to vote with what the party tells you, not what the electorate tells you.”
Labor candidate Eric Kerr, who has long pushed for his party to do more for refugees, welcomed the passing of the medical evacuation bill through Parliament and said the government's "lack of compassion was obvious".
"There are people in our care who need immediate medical attention," he said.
Mr Kerr said when an Australian government last lost a substantive motion in the House of Representatives 90 years ago, Indi ended up with a Labor MP at the next election.
Liberal Party Indi candidate Steve Martin said if he was the Indi MP, he would have sided with the government to "keep our borders strong and make sure there's stability in the policy".
"We've been here before and it led to a lot of deaths at sea," he said.
"There are medical facilities there and mechanisms so if help's needed, that can happen."
Mr Martin said it was important for candidates to be open with their views from the start, so voters know where they stand.
National Party candidate Mark Byatt could not be contacted for comment.
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