The Mail on Sunday and MailOnline published a letter from Meghan Markle to her father to satisfy readers' "curiosity" it had "deliberately generated", the High Court has heard.
The duchess is suing for invasion of privacy and copyright infringement after articles reproduced parts of a letter she sent Thomas Markle.
Their publisher denies the allegations.
It argues the Duchess of Sussex had no reasonable expectation of privacy and anticipated publication of the letter.
Meghan is suing Associated Newspapers after two articles in the Mail on Sunday and three on MailOnline published parts of a handwritten letter to Mr Markle, 75, in February 2019. She has also accused them of data protection breaches.
She claims contents of the letter to her father were selectively edited in a misleading and dishonest manner.
At Friday's virtual preliminary hearing, the publisher's legal team asked for parts of her case to be struck out.
The publisher said Meghan's claim that her father was "harassed" and "manipulated" should not form part of her case and was "objectionable".
Antony White QC, representing Associated Newspapers, told Mr Justice Warby that some of the allegations made by Meghan were irrelevant and not made with a proper legal basis.
'Stir up issues'
He added that the allegations relating to her father were made without any attempt to contact him to see if he agrees with them.
"In this context it appears that the claimant has seen fit to put these allegations on the record without having spoken to Mr Markle, verifying these allegations with him or obtaining his consent (she admits ... that she has had no contact with him since the wedding)," he said.
In court documents prepared for the hearing, Mr White said the duchess alleged the publisher was "one of the 'tabloid' newspapers which had been deliberately seeking to dig or stir up issues between her and her father".
"This is an allegation of seriously improper deliberate, i.e. intentional, conduct to the effect that the defendant's motive was to seek to manufacture or stoke a family dispute for the sake of having a good story or stories to publish," he said.
Mr White told the court that such "complex tests of mental state" of the publisher were "irrelevant to the claim for misuse of private information", and asked the judge to strike out that claim.
He also objected to the duchess's allegation that the publisher "acted dishonestly" when deciding which parts of her letter to her father to publish.
"It is extremely common for the media to summarise or edit documents when reporting current events, and that is not a basis for an allegation of dishonesty," he added.
David Sherborne, acting for the duchess, said the letter had been reported for "the sole and entirely gratuitous purpose of satisfying the curiosity of the defendant's readership about the... private life of the claimant, a curiosity deliberately generated by the defendant".
No attempt had been made to contact the duchess prior to publication in a "deliberate" move "to secure the enormous 'scoop'", he said.
Mr Sherborne argued additional articles published by Associated Newspapers about the duchess should be taken into consideration in support of her privacy action, but not as part of the claim.
He said: "It is very much about the claimant's state of mind."
Mr Sherborne added this was about "the distress she feels about the realisation that the defendant has an agenda and that this is not a one-off" and not about damage to reputation.
It is understood Harry and Meghan, who have relocated to California after stepping back as senior royals, listened to the parts of the hearing.
Associated Newspapers had asked for Friday's hearing to be postponed due to the Covid-19 pandemic but the duchess's legal team rejected this and said she "considered it was unreasonable to accept the offer".
Instead the hearing was held remotely with Mr Justice Warby sitting in his court in front of several computer screens while counsel called in from elsewhere.
Mr Justice Warby said at the end of the hearing that he would give his ruling on Associated Newspapers' application at a later date, but hopefully within a week.
Last week Harry and Meghan announced they would no longer work with several British tabloid newspapers, including the Mail as well as the Sun, Mirror and Express, over "distorted, false or invasive" stories.