Mr Boyd told the court he had received the new information on Thursday and enquiries were carried out on Friday.
In an unexpected development, Scotland's Lord Advocate Colin Boyd QC told the judges on Monday it was impossible to proceed without further enquiries.
Although some witnesses will be heard on Tuesday, the judges, with defence agreement, agreed then to adjourn the trial until Tuesday, 17 October.
On Monday the court at Camp Zeist in Holland was due to hear more evidence relating to the special defences of incrimination put forward by the two accused men.
They have denied all charges against them, blaming others for the atrocity including Mohamed Abo Talb, a former commander in the Palestinian Popular Struggle Front.
Talb, who was jailed for life in 1989 for bombing an airline's office in Copenhagen, was expected to give evidence as a prosecution witness on Monday.
The prosecution declined to comment further on the delay and a Crown Office spokesman said: "We can give no further information other than that given to the court by the lord advocate."
Mr Boyd told the court he had received the new information on Thursday and enquiries were carried out on Friday.
He said: "The matters raised by this information are of some complexity and considerable sensitivity. They relate not to the Crown case but to the defence case.
"Enquiries are continuing but it is likely, though not certain, that I will conclude that the information ought to be disclosed to the defence.
"However there are a number of difficult issues which require to be resolved before any disclosure is possible.
"The sensitivity of the enquiries is such that I am unable to give any further explanation at this stage."
William Taylor QC, defence counsel for Al Megrahi, told the judges he was "as much in the dark" as them about the reasons for the adjournment and therefore in no position to object to it.
However he added: "I am conscious that my client has now been in custody for some considerable time and any delay further extends that period."
Richard Keen QC, defending Fhimah, said: "It's obviously unfortunate the accused should have been in custody for one and a half years while 57 days of a trial has taken place.
"But the lord advocate was good enough to speak to myself and Mr Taylor before and I fully accept he has obligations incumbent on him in the public interest."
Presiding judge Lord Sutherland said that while a disruption to the proceedings was "unfortunate" the judges accepted the adjournment motion.
He said: "We will adjourn until next Tuesday for enquiries to be made. All we can do is express the hope that there will be sufficient time to resolve the difficulties."
However, he added that the court would sit on Tuesday morning to hear evidence from four witnesses, the majority of whom were understood to have evidence relating to passports.