The WA Farmers Federation has attacked Liberal Party advertisements it says try to trick people into believing the lobby group has endorsed the party.
The Liberals this week paid for wrap-around advertisements in rural newspapers Countryman and Farm Weekly which resemble the front page of a newspaper.
The ads gave the Liberals a better score than the Nationals on key election issues under the Federation logo.
The Federation's Dale Park says the ads are misleading.
"We do value our brand so we don't like people using it without actually asking us whether we can or not, which of course in this case the Liberal Party didn't," he said.
"The other part of it is we don't actually endorse any political party.
"What we're saying is have a look at the policies and make your own judgements."
Meanwhile, the National Party is being probed over allegations of inappropriate advertising in Geraldton.
The party has been using illuminated road-side signs around the city to spruik their candidate for the seat of Geraldton, Shane Van Styn.
The WA Electoral Commission says any political signage must display an authorisation note.
The Nationals' Geraldton Campaign Manager, Gerry Gould, accepts the signs do not have the note and the situation is being rectified.
"Yeah, I'm in the throes of doing it right now," he said.
"It's a fast moving campaign and it's just something that's slipped under the radar."