AUGUSTA — A California billionaire’s political operation is entering Maine’s three-way race for governor and will target 90,000 potential voters who it believes can help defeat Republican Gov. Paul LePage, the group’s chief strategist said on Wednesday.

The political action committee NextGen Climate says said it’s launching a targeted program in Maine that will include ground operations and paid advertising in an effort to convince voters to back Democratic candidate Mike Michaud.

“A vote for anyone else, including Eliot Cutler, is in effect a vote against climate, against jobs, against moving the state of Maine forward,” said Chief Strategist Chris Lehane.

The PAC, started by billionaire environmentalist Tom Steyer, will be calling voters, going door-to-door and using paid advertisements, he said. It has begun work in Portland will also be canvassing in Bangor, Lewiston, Auburn and Saco.

Lehane slammed LePage for his past remarks on climate change, like when he the state could benefit from it through the opening of a new maritime shipping route, the Northeast Passage.

The governor’s campaign defended his environmental record and said he understands that Maine’s natural resources are the backbone of its economy, pointing to his issuing the second-largest environmental penalty in the state’s history. Furthermore, LePage believes in climate change, said campaign spokesman Alex Willette.

“He believes that in order to make a true benefit, the world is going to have to start looking at it,” he said, noting that foreign countries are some of the biggest polluters.

Steyer had originally pledged to spend as much as $50 million of his own money and match that from donors to make climate change a key issue in the midterm elections. But his group is on pace to raise far less money than promised.

It has shifted its focus to the ground game, putting staffers in states like Maine to try to influence and turn out voters on Election Day. The group will also be working in Senate races in Colorado, Iowa, Michigan and New Hampshire and governor’s races in Florida and Pennsylvania.

NextGen will have several staffers working in Maine and has already reported spending about $200,000 in the state. Lehane declined to say how much money the group is willing to spend or how many people it would have working or volunteering in Maine.

It plans to work closely with the Maine League of Conservation Voters and the Maine People’s Alliance and use the networks of supporters they’ve already established in the state.

Cutler spokeswoman Crystal Canney said that Next Gen’s effort in Maine is the latest effort among outside groups to spend large amounts of out-of-state dollars for Michaud to “provide cover for his weak record on the environment and a host of other issues.”

She said the effort is about politics, not protecting the environment and pointed to Cutler’s achievements, like helping craft the Clean Air and Clean Water Act while working for Maine Sen. Edmund Muskie.

LePage is also being targeting by other powerful environmental groups, like the League of Conservation Voters, which recently listed him as one of the “dirty dozen” candidates it hopes to defeat this year.

The group has given $250,000 to the Maine Conservation Voters Action Fund, which is running television ads criticizing the Republican governor praising Michaud’s efforts to protect Maine’s waters.