LONDON - Prince Harry on Wednesday fought to take his phone-hacking lawsuit against Rupert Murdoch's UK newspaper arm to trial, asking London's High Court to let him rely on an alleged "secret agreement" between Britain's royal family and the publisher.

Harry, the younger son of King Charles, is suing Murdoch's News Group Newspapers (NGN) for multiple unlawful acts allegedly committed on behalf of its tabloids, the Sun and the now-defunct News of the World, from the mid-1990s until 2016.

NGN, which has settled more than a thousand phone-hacking cases over the past decade, applied in April to strike out Harry's claim, arguing he should have taken action sooner.

Harry says he did not bring a lawsuit until 2019 because of an agreement between Buckingham Palace and senior figures at NGN to delay any lawsuits by the royal family until the end of all other phone-hacking litigation brought against NGN. NGN denies there was any such agreement.

On Wednesday, Harry's lawyers sought to rely on the alleged agreement to defeat NGN's bid to throw out his case and allow it to be heard at trial in January, which will feature a similar claim by British actor Hugh Grant.

Harry alleges NGN journalists or private investigators acting on their behalf unlawfully intercepted his voicemail messages, commonly known as phone-hacking, and obtained private information such as phone bills and medical records by deception, which NGN denies.

David Sherborne, representing Harry, argued there was clear evidence of an agreement between NGN and the royal family, which meant Harry was unable to bring his lawsuit earlier.

The fifth-in-line to the throne said, in a witness statement made public in April, that NGN settled his brother Prince William's claim "for a huge sum of money in 2020... without any of the public being told".

Buckingham Palace has not commented and William's office previously said it could not comment on ongoing legal proceedings. NGN declined to comment in April on whether it made a settlement with William.

Harry also said his attempts to progress his case against NGN, with the backing of the late Queen Elizabeth, were stonewalled by NGN and royal aides.

Royal staff were in communication with Rebekah Brooks - now CEO of Murdoch's British arm News UK - and News Corp Chief Executive Robert Thomson about Harry's lawsuit in 2017 and 2018, according to emails released in April.

Sherborne argued in court filings on Wednesday that NGN had not provided any evidence from Brooks and Thomson "despite their evidence having been identified as critical".

NGN's lawyers said that it had not provided evidence from Brooks and Thomson as they were not working at NGN in 2012 when the agreement was allegedly struck.

The publisher also argues that, even if there was a secret agreement between Buckingham Palace and the publisher, it would not apply until the end of other phone-hacking claims.

Harry's lawsuit against NGN is one of four cases he is bringing against British newspaper publishers, including a similar claim against Mirror Group Newspapers (MGN) in which he is seeking damages of around 440,000 pounds ($560,000).

He became the first senior British royal to appear in a witness box for more than 130 years when he gave evidence in his MGN lawsuit last month.

(Reporting by Sam Tobin; Editing by Devika Syamnath)