Prime Minister Scott Morrison has attacked Labor's plans to lift Australia's refugee intake, saying the nation "would be paying for it for decades".
Costings from the Finance Department show lifting the annual humanitarian intake to 32,000 would cost an extra $6.2 billion.
The analysis covers settlement, welfare and health costs.
"The great risk here is that it will cost taxpayers $6 billion and put at risk the services already experiencing pressure under the current program," Mr Morrison told The Australian on Friday.
The long-term calculations are based on Labor's policy to raise the refugee intake from 18,750 to 27,000 per year by 2025, with the extra 5000 places planned to be funded by churches, community groups and councils.
Labor frontbencher Anthony Albanese rubbished the "nonsense" costings.
"It shows yet again the government isn't focused on governing, it's focused on putting out these nonsense reports," he told Sky News.
"Usually it gets found out that Treasury and Finance and no one has anything to do with them, and they were done on the back of a Wheaties packet.
"I don't know why they just talk about billions. Why don't they talk about trillions, given they just make stuff up all the time?"
Finance Minister Mathias Cormann stood by the costings and argued the Labor Party was prioritising refugees over farmers.
"These are completely misplaced priorities, this is not in touch with what the Australian people want their government to do," Senator Cormann said.
"The Australian people want their government to support drought-stricken farmers."
The Morrison government has reopened the Christmas Island detention centre to accommodate up to 600 asylum seekers it anticipates could be transferred from offshore detention for medical treatment at an estimated cost of $1.4 billion - or $2.3 million per person.
