The Attorney-General's Department has reported a 27 percent year-on-year jump in arrests based on evidence acquired through telecommunications intercepts.
The department said in an annual report that the increase was almost solely driven by NSW Police, whose intercept arrest figures more than doubled to 1070 over the past year.
"Access to these investigative tools is crucial in tackling serious criminal activities such as terrorism, murder and drug trafficking," the Australian Attorney General Robert McClelland said.
Terrorism as a reason for the issue of intercept warrants fell dramatically for the Australian Federal Police (AFP), which was granted 61 warrants for these types of investigations, down from 141 last year.
There were 104 terror related intercept warrants issued across all law enforcement, down from 170 last year.
A much larger focus of the AFP's intercept programs was drug offence investigations, which rose from 391 in 2009-10 to 443 this year.
There were three intercept warrants issued to assist investigations into child abuse material and 18 for cybercrime, with the latter category down from 39 in 2008-09, but up from the seven last year.
Prosecution success rates
The department credited intercept laws with a 22 percent rise in prosecutions based on information derived from surveillance devices.
Convictions and prosecutions based on intercept warrants declined by 7 percent and 24 percent respectively year-on-year, according to the report.
The report cautions though that the number of prosecutions may lag the period that the intercept evidence is acquired, accounting for any discrepancy in the figures.
The use of surveillance devices by Federal law enforcement agencies increased.
The agencies were issued 529 warrants permitting the use of optical, listening, data, tracking and retrieval devices in the past financial year.
The AFP obtained 406 warrants to use multiple surveillance devices, up 29 percent on last year, according to a separate surveillance report. State police figures are reported separately.
Requests to access stored telecommunications data held by carriers continued to dwarf the number of warrants issued for live communications.
Despite a decline of 40,000 requests for stored data in the past year, the method was still invoked 243,000 times, predominantly by police, but also by federal agencies such as the Australian Taxation Office and the Department of Immigration.
Costs of surveillance
The total cost of supporting intercept-based investigations rose mildly, from $46 million in 2009-10 to $50.4 million in the current period.
While most agencies' interception costs remained relatively flat, the Queensland Police Service's spending rose almost $2 million, from $3.3 million in 2009-10 - when its intercept program commenced - to $5.2 million this year.