Pakistan Peoples Party (PPP) Senator Sherry Rehman on Tuesday claimed Pakistan International Airlines (PIA) boarded her on the wrong plane as she was travelling to Garhi Khuda Bux for the death anniversary of slain former prime minister Benazir Bhutto.

"PIA boarded us on the wrong ATR for Multan instead of Sukkur," she tweeted.

Rehman later added that she was now on the right flight "but no bakra in sight", referring to a goat 'sadqa' made by the national flag carrier that made headlines after the first ATR aircraft was cleared for take off following the PK-661 ATR plane crash.

PIA Spokesman Danyal Gilani, responding to media queries, said an inquiry has been ordered into the incident.

"Please note that two ATR aircraft were parked on adjacent bays at the Karachi airport, departing for Multan and Sukkur at almost the same time. Due to some confusion, the coach driver dropped her at the wrong bay," a statement released by the PIA spokesman said.

"However, as she approached the aircraft operating for Multan, the staff present outside the aircraft, corrected her and guided her to the other aircraft which was parked a few steps away," the statement added.

"Such instances are very rarely reported but confusion may occur in case of simultaneous departures. To avoid this, airlines have checks at multiple levels where boarding cards are checked and any such passengers can be intercepted," Gilani said.

The boarding mix-up comes at a time Pakistan's national flag carrier is facing intense public and media scrutiny after the PK-661 air crash earlier this month.

Since the Dec 7 PIA plane crash near Havelian this month, several incidents of flight diversions and delays caused by technical issues have embroiled the airline.