US district judge Sidney Stein said that the writers, including Michael Chabon, Ta-Nehisi Coates and comedian Sarah Silverman, did not have a strong enough interest in the New York cases to justify letting them intervene.

The writers had sought to convince the New York court to dismiss the cases against OpenAI and Microsoft, OpenAI’s largest financial backer, or move them to California. The California court rejected a related request last month.

“It’s unconventional to proceed with the same claims in different places but certainly something we are equipped to handle,” the writers’ attorney Joseph Saveri said in a statement on Monday.

Representatives for OpenAI did not immediately respond to a request for comment. Spokesmen for Microsoft, the New York Times and the Authors Guild declined to comment.

Several groups of copyright owners have sued major tech companies over the alleged misuse of their work to train generative artificial-intelligence systems. The authors in the California case sued OpenAI last summer, accusing it of using their books without permission to train the AI model underlying its popular chatbot ChatGPT.

The Authors Guild filed a similar lawsuit in New York in September on behalf of other writers including John Grisham and George RR Martin. That lawsuit was followed by additional complaints from nonfiction authors and the Times.

The California authors told Stein that allowing the “copycat” cases to continue would lead to inconsistent rulings and waste resources. But Stein on Monday said that the California and New York cases had “substantial differences.”

“More importantly, for the claims that do overlap, the California Plaintiffs have no legally cognisable interest in avoiding rulings that apply to entirely different plaintiffs in a different district,” Stein said.