The firm that spearheaded the Coalition's campaign against Labor's franking credits policy has been forced to destroy all personal information it collected.

Wilson Asset Management, which collaborated with Liberal MP Tim Wilson on a "Stop The Retirement Tax" campaign, has entered into an enforceable undertaking with the privacy regulator after a five-month investigation found it failed to handle information properly.

Fund manager Geoff Wilson and MP Tim Wilson. Credit:Dominic Lorrimer/Alex Ellinghausen

The database was used to gather more than 1000 submissions for a taxpayer-funded parliamentary roadshow and air concerns about Labor's plan to strip tax refunds worth thousands of dollars from retired shareholders who had not paid tax.

It was later linked to invitations to Liberal Party fundraisers, unsolicited advertising from the company and credited as having a key role in the outcome of the federal election.