Pendle has been identified as one of 16 authorities in England at the greatest risk of electoral fraud.
The borough was named in an Electoral Commission report as an area where members of certain communities could be at risk of becoming victims of fraud.
Burnley, Hyndburn and Blackburn and Darwen were also named.
In a bid to tackle the problem, the commission is calling for voters to be required to show photo ID at polling stations at future elections.
But it has rejected calls to restrict access to postal voting, saying it would prevent many innocent people from casting their vote.
However, it said the existing code of conduct needed to be strengthened to ensure campaigners do not handle postal votes or voting application forms and warned it would seek legislation if the problem was not resolved voluntarily.
There has been concern about postal vote fraud at elections in Pendle for several years, and although panels have been set up to investigate allegations on the matter, nothing has ever been proved.
Don’t miss this week’s Leader-Times newspaper for more on this story and local reaction.