Female staffers at NBC News are complaining they felt under huge pressure to sign the “women’s letter” defending Tom Brokaw against sexual harassment allegations.

After former colleague Linda Vester claimed he “groped and assaulted” her in the ’90s, plus an anonymous assistant alleged he had made unwanted advances, more than 115 women signed the letter hailing the veteran anchor as “a man of tremendous decency and integrity.”

Big names backing Brokaw include Rachel Maddow, Mika Brzezinski, Andrea Mitchell and Maria Shriver. Brokaw angrily denied Vester’s claims, likening them to “a drive by shooting.”

One NBC News staffer said, “We felt forced to sign the letter supporting Brokaw. We had no choice, particularly the lower level staffers. The letter was being handed around the office and the unspoken threat was that if your name was not on it, there would be some repercussion down the road. Execs are watching to see who signed and who didn’t. This was all about coming out in force to protect NBC’s golden boy; the network’s reputation is tied to Brokaw . . . If more women come forward, that’s a big problem.”

Another insider said the powerful names on the letter could intimidate other victims. “When you have over 100 women like Andrea Mitchell signing a letter of support without knowing the facts, it’s pretty scary . . . The letter will have a chilling effect on other women coming forward.”

An NBC News rep said, “The letter is a purely grass-roots effort, led by women outside of the company who are motivated by their own support for Tom Brokaw . . . Management has played absolutely no role whatsoever.”

Except the letter was led by Goldman exec Liz Bowyer — who also happens to be a producer for Brokaw’s NBC doc unit and has worked on two of his books.

Meanwhile, Megyn Kelly cautioned her Brokaw-supporting colleagues that there could be more to this: “You don’t know what you don’t know, and that’s not in any way to impugn Tom, who I love and who’s been so good to me. Just saying, you don’t know what you don’t know.”