Vodafone Group Plc released its first Law Enforcement Disclosure report disclosing the secret wires allow some government agencies to listen to conversations on its networks.
Vodafone said it could not give a full picture of all the requests it gets, because it is unlawful in several countries to disclose this information.
"In a small number of countries the law dictates that specific agencies and authorities must have direct access to an operator's network, bypassing any form of operational control over lawful interception on the part of the operator," the UK-based company said.
Vodafone has not named the countries where this can happen.
"The need for governments to balance their duty to protect the state and its citizens against their duty to protect individual privacy is now the focus of a significant global public debate," the company said in the report. "We hope that ... disclosures in this report will help inform that debate."
Communications companies started publicly releasing authority requests after documents leaked by former U.S. National Security Agency contractor Edward Snowden a year ago exposed the range of government surveillance tactics, prompting a public backlash.
Vodafone's report, which covers agency and authority demands for lawful interception and communications data for the period 1 April 2013 to 31 March 2014, provides a detailed insight into the legal frameworks, governance principles and operating procedures associated with responding to demands for assistance from law enforcement and intelligence agencies across 29 countries.
For some of the 29 countries, including Egypt, India, and Turkey, it is forbidden by law to disclose what type and how many requests carriers receive from authorities, Vodafone said. Vodafone also said it doesn’t comply with demands that are unlawful.
In some countries that are experiencing "significant political tension," it is difficult to inquire about matters related to national security without potentially putting employees at risk of harassment or sanctions, Vodafone said.
Vodafone plans to update it at least annually in future and can be found online at www.vodafone.com/sustainability/lawenforcement.