Speaking to Al Jazeera, Mr Mesbahi said: "Iran decided to retaliate as soon as possible. The decision was made by the whole system in Iran and confirmed by Ayatollah Khomeini.
"The target of the Iranian decision makers was to copy exactly what's happened to the Iranian Airbus. Everything exactly same, minimum 290 people dead. This was the target of the Iranian decision makers."
US Defence Intelligence Agency cables at the time reported that the leader of the PFLP-GC had been paid to plan the bombing, the broadcaster said.
The Crown Office has previously said the alleged involvement of the PFLP-GC was addressed at the original Lockerbie trial.
A successful application from Megrahi's family to the Scottish Criminal Cases Review Commission (SCCRC) could start the third appeal into the conviction.
Megrahi lost his first appeal in 2002, one year after he was found guilty of mass murder and jailed for life.
The SCCRC recommended in 2007 that Megrahi should be granted a second appeal against his conviction. He dropped his appeal two days before being released from prison in August 2009 on compassionate grounds.
In December, the Libyan attorney general announced he had appointed two prosecutors to work on the case. For the first time they met Scottish and US investigators who are trying to establish whether there are other individuals in Libya who could be brought to trial for involvement in the attack.
