Finance Minister Mathias Cormann won't comment on reports the Turnbull government is eyeing yet more foreign aid cuts in the May budget.
The coalition is considering a $400 million a year cut to the overseas aid budget, Fairfax Media reported on Thursday.
Senator Cormann would only say the budget would be handed down in May when asked by reporters in Canberra whether the report was true.
Labor frontbencher Penny Wong has called on the Coalition to reject further aid cuts.
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The senator has told Sky News it's a test for Foreign Minister Julie Bishop.
"I hope she is fighting them and I hope she wins because she knows that this undermines Australia's standing and influence in our region at a time where that standing and influence is important for our national interest."
In February, Senator Wong committed a future Labor government to increasing aid investment beyond existing levels.
Labor also highlighted a line from the government's recent Foreign Policy White Paper which stated Australia's foreign aid program was in the national interest.
Minister for International Development and the Pacific Concetta Fierravanti-Wells dodged questions about potential cuts in Senate question time this week, saying the government had previously announced it would maintain its aid budget at about $4 billion for the next two years.
Greens leader Richard Di Natale said the proposed cuts are mean.
"The last thing we should be doing is cutting aid for the world's poorest people. These are people who are living on a few dollars a day, people who don't have access to health and education," he said on Sky News.
"It's a great investment, international aid, it's a sensible investment, but it's the right thing to do. I think it's immoral for a country to be cutting its aid budget."
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Australian Council for International Development chief executive Marc Purcell said the new reports indicated an about-face from the government.
"Let's be clear, this is not about fiscal austerity, it's a choice," he said in a statement.
"Only yesterday, the minister gave a reassurance to parliament that the budget would be maintained at about $4 billion, seemingly consistent with plans laid out last year."
Earlier this week, an Organisation of Economic Co-operation and Development review criticised successive cuts to Australian aid spending.
"The decline in aid flows, despite steady economic growth, has affected the scope of development and humanitarian programs," the review's chair Charlotte Petri Gornitzka said.
"We encourage Australia to find a way to reverse this trend."
Projections indicate levels of Australian assistance could drop to "an all-time low" of 0.22 per cent of gross national income in 2017/18.
