The handling of paperwork associated with the Arlene Arkinson inquest is a "documentary disaster", her family's lawyer said.
More than 35,000 papers are before the long-delayed hearing into the schoolgirl's disappearance in August 1994.
Coroner Brian Sherrard said good progress had been made so far and occasionally cases of this magnitude would suffer from blips. He called a review for Wednesday.
Arlene, 15, from Castlederg, Co Tyrone, went missing after a night out across the border in Co Donegal.
Her body has never been found.
Family barrister Henry Toner QC said: "The situation that has arisen is a documentary disaster. It has been brought about by the police."
He claimed the issues had been apparent for quite some time.
"There still remain outstanding a considerable number of documents from police."
The matter will now be intensively reviewed.
Kevin Rooney QC, barrister for the PSNI, said it was unfair to describe it as a documentary disaster.
"We have over 35,000 documents before this particular inquest."
He said he wanted to speak to retired detective chief superintendent Eric Anderson about issues which arose during his recent evidence to the inquest.
Mr Sherrard said Mr Anderson had mentioned quite a "high octane" surveillance operation.
The lawyer for the police said: "Since he gave his evidence the police have been searching for documentation regarding the surveillance."
The coroner said they were investigating a period when material was not digitalised in the way it is now and it was not unusual to come across documents that were not apparent earlier.
"I would rather that this inquest is conducted correctly as opposed to being necessarily conducted quickly, although if we can have both that would be best."
Arlene was last seen with child killer Robert Howard, who was acquitted of her murder in 2005 by a jury which was not told about his conviction for killing another teenager in south London several years earlier.
But Howard, 71, remained the prime suspect in the Arkinson case until his death in prison last year.