One of the world’s top female explorers has quit the famed Explorers Club after being accused of ethics violations, Page Six is told.

Vanessa O’Brien, who has climbed K2 and Mount Everest, was slammed by club bosses for discussing club president Richard Wiese’s romance with submarine explorer Christine Dennison at a board meeting. O’Brien resigned in July before a disciplinary hearing that her lawyer said was part of an “unrelenting drive” to boot her.

The club accused O’Brien of bullying and sent her a warning note. O’Brien was also accused of calling Janet Walsh, the head of the club’s ethics committee, “most unpleasant” and “horrible.” A source told us: “Something very strange is going on …There is a degree of instability among the board.”

In her letter of resignation, O’Brien, who this year became the first woman to reach Earth’s highest and lowest points, said she found the club to be more focused on “petty infighting and score-settling” than exploration and science. O’Brien said she brought up Wiese’s affair fearing it would be made public.

O’Brien didn’t comment further.

In March, Dennison told The Post that she and Wiese became involved shortly after she joined the club in 2003 — and then found out he was also dating the club’s executive director, Nicci Young, now his wife. Wiese maintains they were both single at the time.

We have also learned that O’Brien’s exit comes as fellow board member Michele Mass was removed and her husband, Jim Edwards, was expelled for allegedly falsely reporting claims of sexual harassment at the club. Edwards claimed that Wiese “harasses everyone” who disagrees with him and sent a complaint to the New York attorney general’s charities bureau, detailing governance and financial issues and a hostile boardroom for women. The Explorers Club insists it investigated Edwards’ allegations and determined they were unfounded.