Michael Bloomberg — likely on the verge of announcing a White House bid — announced Wednesday that he will spend $15 million to $20 million on a voter registration drive in battleground states to help the Democrats defeat President Trump in the general election.

The billionaire and three-term former New York City mayor touted the investment a week after he revealed plans bankroll $100 million in ads targeting Trump in battleground states

“Mike is taking the fight directly to Trump where it matters most — in general election battleground states,” said Bloomberg spokesman Jason Schechter. “He did it last week through a $100 million digital ad buy. He’s doing it this week at the ballot box.”

The voter registration campaign aims to enroll under-represented black, Latino, Asian and younger voters in Arizona, Michigan, North Carolina, Texas and Wisconsin.

Bloomberg backers were on the ground in Arizona this week and contacted Democratic Phoenix Mayor Kate Gallego, The Post has learned.

“Mayor Bloomberg’s team reached out to us to let us know they would be visiting Arizona. Arizona will be a critical state in the 2020 election — we believe the path to the presidency runs directly through Maricopa County,” Gallego said in a statement.

However, she added that she “will not be endorsing any candidates until next year.”

Gallego has participated in a training program for new mayors funded by Bloomberg at Harvard University.

The Arizona Democratic primary will be held on March 17, two weeks after 14 states vote on March 3 — Super Tuesday.

The 77-year-old has already filed papers to appear on the ballot in several states, including Alabama and Arkansas.

Bloomberg’s staggering financial commitment to register Democratic voters and run attack ads against Trump shows he’s all in to defeat the incumbent — even if he doesn’t win the Democratic nomination, campaign sources said.

The spending announcements come as Bloomberg continues to position himself for a likely run.

The media mogul stunned the political world Sunday by apologizing for the New York City Police Department’s aggressive stop-and-frisk searches while he was mayor, after zealously defending the policy for more than a decade.

He made the mea culpa during a speech at the Christian Cultural Center, one of the city’s largest African American churches in the East New York section of Brooklyn.

“I can’t change history,” Bloomberg told congregants. “Today, I want you to know that I realize back then I was wrong, and I am sorry.”