The NUJ has condemned calls by politicians, including Prime Minister David Cameron, for news organisations to hand over to police unbroadcast or unpublished material from coverage of the riots without a court order.
The union wants all media organisations to make strong representations to the court to protect the confidentiality of journalistic material under the Police and Criminal Evidence Act and under the European Convention on Human Rights.
It said: "There are special protections for journalistic material and procedures that the police should follow and the NUJ will seek to defend the confidentiality of journalist's material and sources.
"The NUJ has a long and proud record in fighting to protect journalists faced with actions over sources or journalistic material. It is important we do not allow the police to use journalists as information gatherers for their purposes. Such a move places all journalists at greater risk when covering public order issues and stops sources coming forward."
"With many accounts of injuries and equipment damage already reported, the calls from politicians to hand-over press material will only increases the risks."
The US-based Committee to Protect Journalists has also condemned the move. CPJ executive director Joel Simon said "Broadcasters must not be obliged to provide authorities with raw footage in the absence of any legal due process. Such demands directly endanger journalists and compromise their ability to report the news."