The government has accused the opposition of planning to spend more on increasing Australia's refugee intake than a fund to drought-proof the country.

Following a trip to Christmas Island to show off the reopened detention centre, Prime Minister Scott Morrison has continued his attack on Labor over border security, seizing on Finance Department figures on their refugee policy.

The figures show the cost of increasing the annual humanitarian intake by 13,000 refugees by 2025 would cost $6.2 billion over 10 years.

"Labor need to be upfront about the cost of their policy to significantly increase our refugee intake, Mr Morrison said in a statement. "$6.2 billion is a lot of money and we need to weigh that against other priorities that matter to Australians."

The increase would take the current humanitarian intake from 18,740 per year to 32,000, including 5,000 community-sponsored places which would not require taxpayer funding.

Labor has dismissed the costings as "false and overinflated".

Treasury costings of Labor's policy, which it took to the 2016 federal election, estimated the increase would by $2.9 billion over eight years.

Shadow immigration minister Shayne Neumann said it was the "latest episode in their unhinged scare campaign."

"Australians understand our nation can be strong on borders and still treat people humanely."

Finance Minister Mathias Cormann compared the figure to the government's plans to set up the Drought Future Fund.

"Our Drought Future Fund would grow to $5 billion over that same period Bill Shorten wants to spend more than $6 billion on further increasing our already very generous refugee program," Mr Cormann said.