A federal magistrate judge reportedly has blocked the US Justice Department (DoJ) from sharing Volkswagen diesel emissions related documents.

According to Reuters, the order, issued late last week by US Magistrate Judge Jacqueline Corley in California, blocks the DoJ from sharing 25m pages of records disclosed by Volkswagen AG with a German law firm.

The report said this was a victory for the automaker, which faces 1,600 securities suits in Germany in connection with the diesel scandal. The company turned over the documents as part of prosecutors' probe of its installing software to hide excess emissions.

The suits collectively seek nearly EUR8.6bn (US$10.3bn) from VW, according to a court filing cited by the news agency.

Reuters noted the DoJ sued VW in Germany in September 2016 over losses in federal government employees' retirement accounts and retained German law firm GSK Stockmann to represent the US government. It want to recover EUR30.8m ($37m) plus interest and legal fees.

Lawyers for Volkswagen objected to the DoJ's planned transfer of the documents and said, if it were successful, all 1,600 plaintiffs would have access to them.

VW had said some Volkswagen submissions in Germany became public in the German press days after they were filed.

"It is likely that at least some of these documents would also be leaked to the press," VW lawyer Thomas Liebscher wrote in an affidavit cited by Reuters.

Judge Corley said a protective order between VW and the government bars the sharing of the documents with the DoJ's German law firm. Corley said GSK Stockmann cannot use the documents obtained by the department "to end-run around German discovery rules".

See also: VW emissions crisis coverage