The home affairs department spent $6.1m on flights transferring refugees and asylum seekers interstate and between detention centres last year, according to new departmental data.
In 2018-19 the department racked up a bill of $5.7m for charter flights and $400,000 for commercial flights, according to an answer to a question on notice provided in December.
The figures exclude standing costs to keep planes at the ready for departmental use and do not include transport costs for personnel accompanying the person being transferred.
The questions on notice also reveal the department spent $111m on legal costs in 2018-19, including $72m on external lawyers and $39m on internal legal expenditure.
Last year’s legal bill is a $19m increase on the $92m the department spent in 2017-18 and is up from $79m in 2016-17, figures in those years’ annual reports show.
The home affairs legal bill also dwarfs that of other major departments including the department of human services, which spent $47.6m last year, the health department ($26m), social services ($7.6m) and treasury ($4.4m).
The shadow home affairs minister, Kristina Keneally, called on the home affairs minister, Peter Dutton, to explain “why these costs within his mega-department … continue to go up year after year and if he is even bothering to keep account of how taxpayers’ money is being administered in his portfolio”.
Keneally accused Dutton of “waste and mismanagement”, citing the $423m contract given to garrison services contractor Paladin and the Australian Federal Police’s unpaid superannuation bill.
Guardian Australia contacted Dutton for comment.
In October 2018 the home affairs department revealed it spent more than $275,000 in 2017-18 challenging requests for urgent medical transfers of asylum seekers and refugees on Nauru and Manus Island.
The Greens immigration spokesman, Nick McKim, said Australia’s immigration detention regime “is not only unnecessarily punitive and cruel, it’s also a colossal waste of money”.
“There are hundreds of people who have been detained for years, many of whom are constantly moved around the detention network, far away from their families and support networks, for no apparent reason,” he said. “The family from Biloela currently detained on Christmas Island is a classic example of this.
“Home affairs is also wasting vast amounts of public funds fighting unwinnable cases in courts and tribunals.”
In the latest figures, the home affairs department also reveals it spent $17m on staff overtime in 2018-19.
The Commonwealth director of public prosecutions disclosed that its prosecution of the whistleblower Witness K, who revealed Australia’s spying on East Timor, and his lawyer, Bernard Collaery, has cost $227,971 to date.
Witness K has indicated he will plead guilty to a summary offence in the ACT magistrates court, while Collaery is fighting the prosecution in the ACT supreme court.