Concern has been voiced that a dispute between police and the Northern Ireland Office over sensitive material will further delay an inquest into the death of former IRA man Kevin McGuigan.
The father-of-nine was shot in the Short Strand in Belfast in August 2015.
His murder prompted a political crisis at Stormont amid claims IRA members were involved in the killing.
A preliminary hearing on Friday heard an update on a long-running process around disclosure of security files.
A separate three-day hearing to consider any applications made by police or the security services to redact evidence on public interest immunity (PII) grounds will take place in December.
Philip Henry KC, acting for coroner Patrick McGurgan, said a disagreement has emerged around the PII process.
PII certificates to redact sensitive material in files in inquests are usually signed by a Northern Ireland Office minister.
Peter Coll KC, acting for the PSNI, said the chief constable proposed to employ a PII process which “does not involve seeking a ministerial certificate in respect of the material that he will put forward to the court for PII”.
Tony McGlennan KC, acting for the Northern Ireland Office, said he understands the security service have “asserted a claim in respect of some material in these proceedings”.
“That will be the subject of ministerial certification so, regardless of this debate, you will have a PII exercise to conduct,” he told the coroner.
“There appears to be a developing difference of opinion in respect of the correct process for PII certification.
“I think we should plan for the fact that this might be a matter that requires adjudication and determination by yourself or another court.”
Mr McGurgan said whether the matter is dealt with by him or another court, that could have the knock-on effect of delaying the part of the PII process.
Dessie Hutton KC, for the next of kin, described what was proposed by the PSNI as “irregular”.
“Our take on what is proposed by the PSNI is that it is irregular, and that if PSNI persist in that position we will be making submissions to your honour at the PII hearing about the weight to be attached to the chief constable’s opinion because he is only a chief constable, not a minister,” he said.
“We’re flagging it up now so as to try and avoid delay.”
Mr McGurgan said he believes it is a “fight between the chief constable and the NIO”, and said it should be ironed out.
Another preliminary hearing will take place on November 7.
The shooting of Mr McGuigan followed the murder of ex-IRA commander Jock Davison in the Markets area of the city three months earlier.
Mr Davison and Mr McGuigan had been involved in a personal dispute.
Police believe Mr McGuigan’s killers suspected him of involvement in Mr Davison’s death.
Mr McGuigan’s death led then-PSNI chief constable Sir George Hamilton to say that the Provisional IRA still existed and some of its members were involved in the murder.
He said there was no evidence that the killing was sanctioned by the organisation.
The killing led to a period of instability at Stormont, and DUP ministers engaged in a series of rolling resignations in protest at the IRA’s alleged involvement in the shooting.
