Candidates who put roadside signs on state road reserves will "not be tolerated", warned the Department of Infrastructure and Energy Resources.

DIER corporate affairs manager Suzie Jacobson said state roads and highways were high-profile sites and were often sought after by candidates.

But signage on such roadsides was illegal.

Slogans of election material could also be an issue and statements such as "Vote 1" could mislead voters. In the last state election there were more than 2000 informal votes because voters only marked a number one candidate.

Tasmanian Electoral Commissioner Julian Type said he would prefer candidates to use signs that specified the proper voting process to avoid votes being counted as informal.

Mr Type said signs and election material must also be properly authorised, and not be contrary to the Vehicle and Traffic Act or local council regulations.

Launceston City Council general manager Robert Dobrzynski said there were no significant problems with political campaign signage during the federal election.

"We would advise candidates in the upcoming state election to check with local councils first before placing campaign signs or parking signage trailers," Mr Dobrzynski said.

Ms Jacobson said DIER would usually contact a candidate if they had election material in a banned place and ask that they remove it.

"We are dependent on people letting us know," she said.

Once the election is called, parties and candidates will be contacted by DIER to be reminded of the rules and regulations on election signage.