Alex Bailin, the lawyer representing prominent British media organizations, insisted at the very least the government must clarify what issues are at stake and what harm they could cause.
Failing to do so, he said, "would have the very serious effect of undermining the public's confidence in this inquest."
The inquest was due to start May 1. But Owen, the coroner, said Tuesday he was "becoming increasingly concerned that due to the complexity of the investigation which necessarily precedes the hearings, that may be a timetable to which it may not be possible to adhere."
The Litvinenko process has been delayed until now because, for a long time, officials thought there was a chance the Russian suspects could be prosecuted. But last year, it became clear that the U.K. would not be able to put the two suspects on trial.
Emmerson said Marina Litvinenko was "extremely disappointed" by the prospect of further delays.
"Not as disappointed as me," Owen said.
The hearing was adjourned until Wednesday.
Cassandra Vinograd can be reached at http://twitter.com/CassVinograd