The US-based monitoring group Human Rights Watch has expressed its concern about the British government's "utter disregard" for the security of the Northern Editor of the Sunday Tribune, Ed Moloney.
Mr Moloney is due in court next week over his refusal to hand over interview notes to detectives investigating the murder of the Belfast solicitor, Mr Pat Finucane.
In a letter sent yesterday to the British prime minister, Mr Tony Blair and the Northern Secretary, Dr Mo Mowlam, Human Rights Watch said the court disclosure order, compelling Mr Moloney to reveal confidential material, "suggests that a journalist who sought evidence of government wrongdoing has become the target of government harassment.
"Forcing Moloney to reveal sources and notes could put him and others in real physical danger, while effectively silencing others who might otherwise speak out on collusion."
Mr Moloney has insisted he will not release the notes, which were taken nine years ago when he interviewed Mr William Alfred Stobie, who has been charged with Mr Finucane's murder.
Mr Moloney used the notes from the 1990 interview in an article published in the Sunday Tribune last June. In the article, Mr Stobie alleged collusion by the RUC in Mr Finucane's murder.
In its letter, Human Rights Watch called on the British government to establish a full public judicial inquiry into Mr Finu cane's death in 1989. It also called on the government to "halt its pursuit of Ed Moloney.
"Notwithstanding the real progress toward peace in Northern Ireland, there has been little progress in building confidence in the government's response to allegations of collusion. Coercing journalists who have themselves explored collusion - while shielding the security services from a judicial inquiry - could further undermine this."
The letter continued: "The added threat of judicial action to force those investigating collusion to disclose what may constitute evidence of gross human rights abuse contrasts vividly, in turn, with the lack of transparency and the very limited nature of the government's inquiries into collusion since the Finucane murder . . . there is a particular need for the government to acknowledge the special needs of the press in Northern Ireland to safeguard themselves and their sources from extra-legal assault - and to protect them from intimidation."
Ms Julia Hall, the organisation's counsel in the Europe and Central Asia division, said the mounting evidence of state-sponsored collusion in Mr Finucane's murder should be the government's focus, "not going after a journalist who must, by the nature of his profession and in the context of on-going violence in Northern Ireland, keep his sources confidential."
The Northern Ireland Office said it would be "inappropriate" to comment on the contents of the letter from Human Rights Watch, stressing the issue was a matter for the courts.