Iranian authorities refused to fuel the aircraft of Pakistan PM Nawaz Sharif during his visit to Tehran last month.
Tehran did it to make the state-run PIA clear its dues amounting to just over $5,000.
Quoting a Pakistan International Airlines official, Times of India reported on Thursday.
"The Iranian airport authorities had refused to fuel the Pakistan PM's aircraft at the Tehran airport on May 12 and warned it would not release the plane until the PIA cleared the outstanding payment," the official said.
"The Iran Air officials responsible for handling the VVIP flight showed their annoyance over the PIA failure in clearing the pending invoice of PK-788 despite the passage of four months."
The warning alerted the PIA bosses who directed its official in Tehran to clear the amount forthwith and save Pakistan from the embarrassment.
The PIA managed to hide the issue from the foreign office and the prime minister.
PIA spokesman Mashhood Tajwar denied the PM's aircraft was held at Tehran airport over payment issue.
According to details, the PK-788 (London to Karachi flight) had to make an emergency landing at the Tehran Airport on January 18, 2014 when a passenger reported some serious health problem and died later.
