PORTLAND – Consumer activist Ralph Nader has lined up behind Oakhurst Dairy in its fight to keep labels that say its milk comes from farms that don’t use artificial growth hormones.

Nader, through his foundation that supports freedom of speech, has offered free legal help to the small Maine dairy in its legal battle against chemical giant Monsanto.

“Oakhurst’s label is completely untouchable. It’s free speech,” said Nader, the Green Party candidate in the last presidential election. “What Monsanto is doing is engaging in frivolous harassing litigation.”

Monsanto has “made a serious tactical mistake” by suing Oakhurst, he said. “I think they’re beatable in the court of law and the court of public opinion.”

Oakhurst President Stanley Bennett II said he and Oakhurst’s attorneys in Portland are assessing Nader’s offer but have yet to decide whether to take him up on it.

“It’s a heartwarming show of support,” Bennett said. “If we need them, it’s nice to know they’re there.”

In a lawsuit filed in U.S. District Court in Boston, St. Louis-based Monsanto accused Oakhurst of misleading labeling and advertising that disparages a Food and Drug Administration-approved product manufactured by Monsanto to increase cows’ milk production.

The dairy asked Wednesday that the case be moved to the federal court in Portland, citing its importance to Maine’s regulation of its milk industry.

Oakhurst noted that only 7 percent of its sales are in Massachusetts and just 1.5 percent of its marketing dollars are spent there.

Monsanto officials did not return phone calls seeking comment.

Oakhurst has been deluged with support since news of the lawsuit came out. Several dozen people seeking to support Oakhurst’s legal defense have sent checks, which the dairy has returned. Groups from Waldo County to California have organized petition drives. The dairy’s milk sales have increased – though Oakhurst is not sure that the legal dispute is driving consumers.

The response has Bennett fielding dozens of calls a day from supportive dairy farmers, biotechnology opponents and consumers.

“I’m terribly inundated with requests for information about the lawsuit,” Bennett said. “I should really be running the business.”

Bennett called all the support “heartwarming” and said it has helped solidify his conviction to engage in what is likely to be an expensive fight with Monsanto.

“It’s our right and obligation, as I see it, to keep people informed as to what is and what isn’t used in the production of the foods they consume,” he said. “All of the responses are supporting our position and suggesting we fight the good fight and don’t buckle under.”