Gard was accused of making a false statement to police about a listening device found in the All Blacks' hotel meeting room before the August 2016 match against Australia in Sydney.
The magistrate was unable to rule out that someone else could have planted the bug, ABC reported.
Gard was found guilty of a second charge relating to carrying out a security operation without a licence.
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The matter, dubbed 'bug-gate' by media, caused much friction between the Australian and New Zealand Rugby unions when it was revealed last year.
The All Blacks management decided not to alert police for five days after the bug was found, waiting until the morning of the test before instructing hotel staff to involve them..
The verdict came a day before Australia play the All Blacks in this year's Rugby Championship opener in Sydney on Saturday.
(Reporting by Ian Ransom; Editing by John O'Brien)
