The hospital's 2014 financial report reveals that management is reviewing its operational performance after posting a $4.9 million deficit last financial year, down from a $1.1 million surplus in 2012-13.
The report said should financial assistance be required, Calvary Health Care ACT may "call upon financial support from the parent entity, Little Company of Mary Health Care".
It comes as the union representing the territory's nursing workforce sought assurances that jobs would not suffer among concerns the hospital's financial doldrums might worsen.
Calvary Hospital's acting chief executive Karen Edwards chaired a wide-ranging staff briefing last week at which issues facing the northside health facility were aired.
Australian Nursing and Midwifery Federation ACT branch secretary Jenny Miragaya met with Ms Edwards the following day and said the issues, including a recent spate of senior resignations, had caused some disquiet among staff.
"I have impressed upon Calvary that their best asset is their staff and their commitment to excellent care," Ms Miragaya said.
"Calvary has a very good reputation and a lot of that is built on the fact they have a skilled staff who are committed to patient care and committed to Calvary."
Ms Miragaya was assured there would be no job losses. However, she was told the hospital was looking to "reconfigure" its staff relief pool.
"They have assured me that nobody who has a permanent position will lose their job," she said.
"But the issue I have is a number of people who request work in the relief pool do so so that they get easier flexibility in managing work-life balance. That's something that we will continue to advocate."
She also sought assurances from Ms Edwards that mandatory training, which had been a concern in the past, would not be sacrificed to get the budget back in black.
As revealed in The Canberra Times on Saturday, the hospital has instituted a temporary staff freeze after posting a loss last year. The hospital was hit by a budget overrun which saw it deliver a "disappointing" financial performance.
Ms Miragaya said although she was not privy to the hospital's budget, she feared the financial situation might deteriorate.
"I am concerned that we're only into the beginning of October and if they've got budget problems now, it is something that will probably get worse," she said.
Mark Doran, the national chief executive officer of Little Company of Mary Health Care, said Calvary had absorbed the budget overrun and the bill would not be footed by ACT taxpayers or the government.
"The disappointing financial performance of Calvary Health Care Bruce last year is something we are actively working to address and we remain committed to the provision of safe, effective and high-quality health services to our community," he said.
Mr Doran said Calvary was keeping ACT Health closely informed about all aspects of the matter.
Ms Miragaya said she had stressed to Ms Edwards that there needed to be adequate communication between management and staff so employees felt "included in the decision making process".