Australian Federal Police boss Andrew Colvin is weighing up what work can be cut as the force confronts significant funding reductions.
The AFP will have its funding trimmed by $205 million over the next four years, compared to its existing levels.
The downturn is partly due to the lapse of time-specific programs including an Asia-Pacific meeting in Papua New Guinea later this year and a completed security mission in the Solomon Islands.
Budget papers indicate the AFP will be expected to shed several hundred staff over the next few years.
Mr Colvin acknowledged work in fighting gangs, drugs and corruption may need to be scaled back to cope with the budget cuts.
The commissioner said a large chunk of his 6500-strong workforce was dedicated to non-discretionary duties, such as airport security and policing in the ACT.
Officers not assigned to these core tasks were spread across fighting organised crime, narcotics, fraud and corruption.
"They're the discretionary areas where I have some ability to re-prioritise my work," Mr Colvin told a Senate estimates hearing in Canberra on Wednesday.
Prime Minister Malcolm Turnbull insisted his government was investing heavily in critical AFP projects.
"There has never been an Australian government that provides more support for the Australian Federal Police than the one I lead," Mr Turnbull told parliament.
The AFP blew this year's budget by $27.2 million due to the elevated national security risk.
The force has put on 80 more staff than set out in the budget papers, with its total workforce costing about $10 million more than anticipated.
Its additional supply costs - which underpin the technologies and systems used in field operations - have cost $9 million more than expected.
An enterprise agreement struck with AFP staff also stung its budget another $7.5 million.
The AFP will receive an extra $22.1 million in the next financial year, $5 million less than it overspent this year.
Labor senator Penny Wong quizzed the commissioner about how the AFP would meet its budget.
"I have a number of levers at my disposal to pull in terms of recruitment, for instance, around my unit costs, around my operational output," Mr Colvin said
Senator Wong pressed the commissioner about whether he anticipated a reduction in crime.
"I would assume that there won't be a reduction, there will be changes in crime," Mr Colvin said.
"And there's always more crime than we can deal with."
AFP's kitty to recruit new staff will be cut by $55 million over the next four years compared to static funding levels, which Mr Colvin confirmed would directly affect the number of members he could employ.
Asked if he would prefer more funding rather than needing to cut programs, Mr Colvin described himself as a realist.
"I wouldn't be the first commissioner to say that I would love more resources, but of course I need to make priority decisions," he said.
