The Duchess of Sussex is seeking a court order to stop the names of five friends being made public in her high-profile legal dispute with Associated Newspapers, one of its titles said on Thursday.

Meghan Markle is suing Associated, its Mail on Sunday newspaper and the Mail Online website, claiming breach of privacy, data protection rights and copyright over the publication of extracts of correspondence to her estranged father, Thomas, after her 2018 wedding to Prince Harry.

The Mail has argued it was justified in publishing the extracts because it said the five friends had revealed the existence of the correspondence in a prior interview with the US magazine People. The five were named as the sources of the article in legal papers submitted by Meghan to the court last month. The newspaper group claims that article gave it the right to publish further extracts.

But the duchess claims she was not involved and now said Associated was threatening to publish the friends' names, Mail Online reported. "These five women are not on trial and nor am I," she was quoted as saying in a witness statement. "The publisher of the Mail on Sunday is the one on trial. I respectfully ask the court to treat this legal matter with the sensitivity it deserves, and to prevent the publisher of the Mail on Sunday from breaking precedent and abusing the legal process by identifying these anonymous individuals."

Earlier this month, the duchess claimed in leaked legal documents she was left "unprotected" by the royal family from "false and damaging" media articles when she was pregnant. Those documents also claimed her friends were "rightly concerned for her welfare".

Meghan and Harry quit frontline royal duties earlier this year, an event dubbed "Megxit", and have waged an increasingly bitter battle with the media, particularly the British tabloid press. The couple now live with their young son, Archie, in California, and have set up a non-profit organisation to promote education, mental health and well-being.