The Australian Federal Police applied for 573 telecommunications interception warrants in the last financial year, according to newly released statistics.
The statistics, part of a response to a question in writing from Greens Senator Scott Ludlam, also shed light on the average length of ‘controlled operations' conducted by the federal law enforcement agency.
Controlled operations are covert or undercover operations where officers are authorised to do things that would otherwise be illegal so they can gather evidence of serious crimes, according to the Attorney-General's department.
The average length of controlled operations in 2008-9 financial year was 84 days. The previous year it was 69 days.
The AFP also provided figures for the 2009-10 financial year. It said covert operations had averaged 54 days in length so far.
Senator Ludlam also received detailed responses on the limits agencies operated in when it came to information gathered by intercepting phone calls.
Specifically, the AFP confirmed that, under some circumstances, information gathered for one crime could be used to investigate others suspected offences.
"Section 67 of the TIA Act allows an agency which has lawfully obtained information by telecommunications interception to use it and to disclose it for a ‘permitted purpose'," the statement said.
"The definition of a ‘permitted purpose' includes use of information to investigate prescribed offences other than offences for which the information was initially obtained.
"The term ‘prescribed offence' includes any offence punishable by at least three years imprisonment."
Information could be shared with a range of agencies for specific investigations under Australian law.