The long-running Bloody Sunday Inquiry is not expected to publish its final report until next year, the families of those who died have claimed.
Lord Saville began hearing evidence in March 2000
Lord Saville and his two colleagues, who opened the inquiry in April 1998, have been trawling through evidence heard from more than 900 witnesses.
The tribunal investigated the deaths of 14 civilians shot by soldiers during a civil rights march in the city in 1972.
The first public hearing was held in March 2000 and closed in November 2004.
It had been expected their findings would have been published by now but the families said they had been told by the Irish government it would not be released until next year.
A spokeswoman for the inquiry refused to give any information on when the report might be released.
"It has been necessary for the tribunal to look at a very large quantity of material, so that it is not possible at this stage to give any firm estimate of when the report is likely to be finished," she said.
However, she said the families and other interested parties would receive "substantial notice" of publication.
SDLP leader and Foyle MP Mark Durkan said a delay would cause further frustration and anxiety for the families.
"The families and injured at least deserve an idea of how much longer they will have to wait. That should not be too much to ask," he said.
The Bloody Sunday inquiry was established in 1998 by Prime Minister Tony Blair after a campaign by families of those killed and injured.
Lord Saville of Newdigate and the Commonwealth judges accompanying him on the inquiry began hearing evidence in March 2000.
The inquiry has heard evidence from leading politicians, including the prime minister at the time, Sir Edward Heath, civilians, policemen, soldiers and IRA members.