Telstra received 40,000 requests for user information from Australian law enforcement agencies in the second half of 2013, the telco's first ever transparency report reveals.
Released on Friday, the report mimics recent efforts by US-based tech firms to shine a light on how law enforcement agencies use telecommunications data during investigations.
The vast majority of requests - about 36,000 - were for customer information or "carriage service records", which can include the date, time and duration of calls and internet sessions as well as email logs from Bigpond addresses.
Customer information includes the kinds of data found on a phone bill, such as name, address, service number, connection dates, and date of birth.
Telstra received 1450 warrants for phone taps and 2871 requests from police, fire and ambulance to release information that could help in emergency situations.
Court orders, typically relating to civil disputes, accounted for 270 requests.
The telco is prohibited from disclosing any information relating to requests from national security agencies such as ASIO.
Nor did it reveal which agencies requested data. Information from the Attorney-Generals department indicates a diverse range of bodies, including the RSPCA, make requests.
Telstra's chief risk officer, Kate Hughes, said the report was an attempt to balance transparency with the telco's legal responsibility to assist with law enforcement requests.
"This assistance is provided for specific reasons, such as enforcing criminal law, protecting public revenue and safeguarding national security," she wrote in the report.
She said its release, a first for an Australian telco, was "aligned with recent international reporting".
Several tech titans including Facebook, Twitter and Google have all begun publishing similar transparency reports, largely in response to increased scrutiny in the wake of the Edward Snowden leaks.
Unlike most of these reports, however, Telstra did not disclose how many of the requests it challenged or rejected.
But because Australian law allows agencies to undertake a pre-warrant check to fine-tune their investigations, there are relatively fewer illegitimate requests, it said.
Telstra said its international arm, Telstra Global, received fewer than 100 requests for information between 1 July and 31 December.
