Rupert Murdoch's News Corp
The internal investigation in Australia followed the phone hacking scandal at News Corp's UK arm, which resulted in the shutdown of its News of the World tabloid.
In a statement, the Australian unit News Ltd
The review's findings provide the strongest possible support for News Limited's assertion that its editorial staff have not commissioned the kind of illegitimate surveillance or payments that have come to light in the UK, the company said.
Still, the company said it will make changes including adopting a single code of conduct across its editorial operations and further strengthening the approval process for any use of private investigators.
The locally listed shares gained 1.0 percent, in line with the broader market's <.AXJO> 0.9 percent rise.
The News of the World was revealed this year to have run an industrial-scale operation to hack into the phones of murder victims including schoolgirl Milly Dowler as well as celebrities and politicians.
The scandal caused a wave of public anger in Britain which ultimately brought about the closure of the tabloid, shook the political establishment and saw the head of the country's largest police force resign.
News Corp executive James Murdoch, son of media mogul Rupert, last week held his line that he was innocent of covering up phone-hacking at the News of the World and blamed other former executives in a parliamentary hearing.
(Reporting by Sonali Paul and Victoria Thieberger; Editing by Ed Davies)