Vic police caught in 20-year gun bungle

For about 20 years thousands of Victorians with secondary gun licences have been over or undercharged by Victoria police.

The 2016 internal review has so far found at least 2500 people, who applied for a second firearm licence since 1997, have been affected.

Superintendent Paul Millett says the mistake related to fees only and nobody has incorrectly been given a firearm licence.

He said the "human error" was caused by police improperly interpreting fees set out in legislation from about 20 years ago.

Licence holders affected by the mistake are expected to receive a letter from the Licensing and Regulation Division before the end of April 2017.