Meghan and Harry tune in to first day of hearing in case against Associated Newspapers

A preliminary hearing opened on Friday at Britain's High Court in the Duchess of Sussex's legal action against a British newspaper that published what she describes as a "private and confidential" letter she wrote to her father.

Meghan is suing the Mail on Sunday and its parent company, Associated Newspapers, for publishing parts of an August 2018 letter she wrote to Thomas Markle.

The civil lawsuit accuses the newspaper of copyright infringement, misuse of private information and violating the UK's data protection law, news.com.au reports.

Associated Newspapers published sections of the letter in February last year. It denies the allegations – particularly the claim that the letter was presented in a way that changed its meaning. The company has said it intends to vigorously fight the case.

Meghan Markle has had 'no contact' with her father since she got married in 2018. Photo / Getty Images

Lawyers for Associated Newspapers want the court to strike out parts of Meghan's case ahead of a full trial, arguing that allegations of "dishonesty and malicious intent" should not form part of her case.

As the hearing opened via video conferencing, Anthony White, a lawyer representing the publisher, told the judge that lawyers for Meghan had made "further assertions of improper, deliberate conduct," and that she accused the publisher of "harassing, humiliating, manipulating and exploiting" Thomas Markle.

It was "highly unlikely" that she had "any credible basis for these allegations of impropriety" towards her father, as she had had no contact with him since she got married to Prince Harry in 2018, he said.

White rejected the duchess's allegations that the publisher had deliberately sought to "manufacture or stoke a family dispute for the sake of having a good story or stories to publish".

He said this was "irrelevant to the claim for misuse of private information", and asked the judge to strike out that allegation.

The lawyer also rejected Meghan's allegation that the publisher "acted dishonestly" when deciding which parts of her letter to publish.

Harry and Meghan were expected to listen in to the part of the hearing conducted by her lawyers.

Thomas Markle's strained relationship with his daughter complicated Meghan's entry into the royal family.

He had been due to walk Meghan down the aisle at her wedding, but pulled out at the last minute, citing heart problems.

The former television lighting director has given occasional interviews to the media, complaining in December 2018 that he'd been "ghosted" by his daughter after the wedding.

The letter was written three months after the royal wedding at Windsor Castle. Analysts have compared the legal case to the late Princess Diana's lawsuit over photographs showing her exercising on gym equipment. The case was settled before it was to be heard.

Prince Harry has long had a difficult relationship with the press.

When the couple announced the legal action over the letter, he accused some newspapers of a "ruthless campaign" against his wife and compared it to how the press treated his mother Princess Diana, who died in a Paris car crash in 1997.

Earlier this week the couple issued a strongly-worded letter announcing they will no longer co-operate with several British tabloid newspapers because of what they called "distorted, false or invasive" stories.

The couple said they won't "offer themselves up as currency for an economy of click bait and distortion."

The couple announced in January they were quitting as senior royals, seeking financial independence and moving to North America.