A British lawyer representing victims of phone hacking by Rupert Murdoch's News International says a significant new email has just emerged in litigation.

David Sherborne told the High Court on Wednesday that the email had been found in March by a law firm representing News International, but had only just been passed to phone hacking victims' lawyers.

He described the document as a significant ''instruction email in relation to a well-known individual victim's phone,'' and said it should have been disclosed earlier.

Sherborne told The Associated Press in a phone call that he couldn't elaborate as Judge Geoffrey Vos had barred attorneys from naming the email's sender, or subject, so as not to prejudice ongoing criminal investigations into hacking at Murdoch's publications.

News International declined comment.

- AP