The presidential campaign of Robert F. Kennedy Jr. has fired a consultant, according to the campaign’s manager, after a video circulated of her urging an audience to support Mr. Kennedy on the ballot in New York because it would help former President Donald J. Trump defeat President Biden.

The consultant, Rita Palma, had falsely identified herself as the New York state director of Mr. Kennedy’s campaign, Amaryllis Fox, Mr. Kennedy’s campaign manager and daughter-in-law, said late on Wednesday, adding that the campaign had fired Ms. Palma “immediately” after seeing the video “in which she gave an inaccurate job title and described a conversation that did not happen.”

In that video, Ms. Palma — who Ms. Fox said had been hired as a ballot access consultant in the state — said that “the Kennedy voter and the Trump voter, our mutual enemy is Biden,” adding, “Whether you support Bobby or Trump, we all oppose Biden.”

Encouraging the audience of Republicans to support Mr. Kennedy, Ms. Palma outlined a hypothetical scenario in which Mr. Kennedy would win enough electoral votes to prevent both Mr. Trump and Mr. Biden from winning 270 electoral votes, pushing the decision to Congress in what is known as a contingent election.

“Right now, we have a majority of Republicans in Congress,” Ms. Palma said in the video, referring to the House of Representatives. “So who are they going to pick? If it’s a Republican Congress, they’ll pick Trump.” In such a scenario, the Senate — which the Democrats currently control — would also elect the vice president.

CNN reported earlier this week that Ms. Palma had also promoted false claims that the 2020 election was stolen from Mr. Trump, whom she repeatedly called her “favorite president.”

Before saying that Ms. Palma had been fired, Ms. Fox said in a statement earlier in the week that “the video circulating was not taken at a campaign event.”

She added: “Palma was speaking as a private citizen and her statements in no way reflect campaign strategy, the sole aim of which is to win the White House.”

Allies of Mr. Trump have been discussing ways to elevate third-party candidates such as Mr. Kennedy in battleground states to divert votes away from Mr. Biden.

Mr. Kennedy has also recently aligned himself closer to Mr. Trump by sympathizing with those who have been convicted of crimes in connection to the Jan. 6, 2021, attack at the Capitol. Mr. Kennedy later retracted many of those comments, saying that his campaign made “unforced errors” when addressing the issue, but stood by his commitment to appoint a special counsel to “look at” the criminal cases of some of the rioters.