Megrahi was convicted of the bombing in 2001
Prosecutors have launched a legal bid to limit the scope of the Lockerbie bomber's appeal against conviction.
Lawyers for Abdelbasset al Megrahi have lodged full grounds of appeal with the Appeal Court in Edinburgh.
But the Crown said it should be limited to the issues raised by the Scottish Criminal Cases Review Commission.
It referred Megrahi's case back to the appeal court last year. Megrahi is serving life for killing 270 people in the 1988 bombing of Pan Am flight 103.
It came down over the Scottish town of Lockerbie.
Megrahi, 56, is currently in Greenock prison serving a life sentence after being found guilty of mass murder after a trial at Camp Zeist in the Netherlands in 2001.
He lost his first appeal the following year.
Last June his case was referred back to the appeal court for a second time by the Scottish Criminal Cases Review Commission (SCCRC) on a number of specific terms, which have never been fully published.
Advocate depute Ronald Clancy QC told five judges, at the Court of Criminal, that the SCCRC carried out an exhaustive investigation and rejected 90 allegations.
These included numerous conspiracy theories about planting and tampering with evidence, he said.
He said Megrahi's team wanted to be able to return to these but that would be tantamount to allowing a second appeal on the same point as the first.
The hearing to decide on the ultimate scope of Megrahi's appeal is being heard by a panel of five judges and is scheduled to last four days.