The revelations come just days before a tell-all interview between Oprah Winfrey and The Duchess and her husband, Prince Harry.
Buckingham Palace said on Wednesday it was "deeply concerned" about claims of bullying made against Meghan, The Duchess of Sussex, and will look further into them.
The claims were made in an article in the Times newspaper on Wednesday ahead of an interview The Duke and Duchess of Sussex have filmed in the United States with Oprah Winfrey.
In a statement unusual for the British monarchy, the palace reacted to news of the claims, according to which a complaint of harassment against assistants had been made in October 2018 when the former American actress was still living with the British royal family.
According to the newspaper, the complaint was made to the palace by Jason Knauf, the couple's communications secretary at the time, a few months after Meghan's high-profile marriage to Prince Harry, grandson of reigning monarch Queen Elizabeth II.
"We are clearly very concerned about allegations in the Times following claims made by former staff of the Duke and Duchess of Sussex," the palace said in a statement.
"Accordingly, our HR team will look into the circumstances outlined in the article. Members of staff involved at the time, including those who have left the Household, will be invited to participate to see if lessons can be learned," it added.
"The Royal Household has had a Dignity at Work policy in place for a number of years and does not and will not tolerate bullying or harassment in the workplace."
Speaking through a spokesman, Meghan, 39, said she was "saddened" by the harassment accusations, which came to light a few days before an interview potentially damaging to the crown.
The Duchess of Sussex is "saddened by this latest attack on her character, particularly as someone who has been the target of bullying herself and is deeply committed to supporting those who have experienced pain and trauma," a statement issued by her spokesman said.
"She is determined to continue her work building compassion around the world and will keep striving to set an example for doing what is right and doing what is good," it added.
The couple's lawyers told the Times that the paper was "being used by Buckingham Palace to peddle a completely false story" ahead of the scheduled March 7 broadcast of the interview of Harry and Meghan by US TV star Oprah Winfrey.
'History repeating itself'
The interview is eagerly awaited in the UK, where the press and royal experts are on the lookout for possible revelations from the couple, who had made no secret of their unease within the royal family before withdrawing from it in 2020.
According to excerpts already broadcast, Prince Harry explained that his "great concern was that history was repeating itself", apparently referring to the death of his mother Diana killed in 1997 in an accident in Paris while trying to escape the paparazzi chasing her.
Citing media pressure and a desire for independence, the couple stepped back from royal duties in April 2020 and moved to the US.
Settling in California with his wife, Prince Harry, 36, sixth in the order of succession to the British crown, has repeatedly denounced the pressure of the media on the couple.
The couple have since signed contracts with Netflix and Spotify in order to become financially independent.
The televised interview with Winfrey comes at a difficult time for Queen Elizabeth II, whose husband, Prince Philip, 99, has been hospitalised for more than two weeks with an infection.
He has recently been transferred to another hospital in London and according to his daughter-in-law Camilla, his condition is "slightly improving".
He "suffers at times," added the Duchess of Cornwall and wife of Crown Prince Charles, adding: "We are keeping our fingers crossed".