REGION - A reward is being offered for anyone who has any information about the whereabouts of 160 election posters for Country Labor Candidate for Finniss, Mary-Lou Corcoran, that have mysteriously vanished this week.

Mary-Lou Corcoran has encountered a hurdle in her effort to win the March 20 state election with the disappearance of over 160 posters from poles throughout the Fleurieu Peninsula.

Victor Harbor was the main area where the posters went missing, plus some in Inman Valley.

"I am very disappointed the election posters are being stolen en masse," Ms Corcoran said.

To make matters worse Ms Corcoran had many more posters tampered with or vandalised.

"I have a fantastic band of volunteers who have taken responsibility for the posters and it is heartbreaking for them to see their work destroyed.

"It is not only the money involved in replacing them it is all the time and effort it took to get them up," Ms Corcoran said.

The cost of the posters are $11.80 each and under the Electoral Act it is an offence to tamper with the posters in any way.

A reward is offered to anyone who has information leading to the person or persons responsible for the theft.

Contact Mary-Lou Corcoran on 0450 872 394 or email - mary-lou.corcoran@alp.org.au if you have any information.

Liberal candidate and member for Finniss, Michael Pengilly said he has encountered similar problems.

"Unfortunately it happens, but it is par for the course come election time," Mr Pengilly said.

"I do not, nor do my supporters touch other candidate's posters," he added.

Victor Harbor resident, Richard Wallman in a letter to the editor this week apologises to the Labor candidate for using her poster for his swimming pool campaign.

"Last week I picked up a Labor poster which was lying in bushes near the Inman River and I thought it would be classified as litter," Mr Wallman wrote.

"I then used the photo section minus the Labor Party logo to enhance my 'Swimming Pool for Victor Harbor' campaign," he added.