The NCA has been given powers under the National Crime Authority Act of 1984 and also by similar legislation enacted by the States and the Northern Territory. The NCA has authority to investigate any offense that involves two or more offenders, substantial planning and organization, the use of sophisticated criminal methods, and commission in conjunction with other similar offenses. Such offenses include theft, fraud, tax evasion, currency violations, drug trafficking, illegal gambling, prostitution, extortion, and public corruption. When the NCA exercises its special functions, it is given powers not available to most law enforcement agencies. These include the power to hold hearings and receive evidence under oath, require the production of documents, order the confiscation of a person's passport, and issue a warrant for the arrest of a witness. Other NCA powers pertain to search warrants, intelligence gathering, the establishment of task forces, telephone interceptions, listening devices, monitoring orders, tax-related investigations, and police powers.