Malaysia Airlines (MAS) has clarified that former prime minister Najib Abdul Razak was not given a waiver for half a tonne of excess luggage during his recent family trip to Langkawi.

MAS said when passengers checked-in as a group, all their luggage might be combined and tagged under a single name, which could "appear on the system as excess baggage."

"In this particular case, the group's total checked-in baggage was well within the allowable limit.

"Malaysia Airlines observes a strict policy on excess baggage and can confirm that no waivers were given," it said in a statement this evening.

The airline also said it was investigating the source of the viral screenshots of Najib's flight details.

The screenshots of what is believed to be MAS' ticketing system showed that Najib was given a waiver of RM17,000 for 535kg of excess baggage for a trip to Langkawi.

A second screenshot also showed there were seven people in Najib's party including his wife Rosmah Mansor, son Norashman, daughter Noooryana Najwa and her husband Daniyar Kessikbayev as well as the couple's 10-month -old son Adam Razak.

Also in the entourage was Najib's stepson Riza Aziz, who was implicated in the 1MDB scandal.

Entourage comprised 17 others

Speaking on condition of anonymity, an aviation industry veteran told Malaysiakini that based on the screenshots, Najib and his family had flown in business class and two of them were platinum members.

However, it is understood that in addition to Najib's family, the entourage also included 17 economy class passengers.

Based on figures made available on MAS' website, platinum members are given an additional 100 percent free baggage allowance based on class of travel - business class' 40kg allowance would be increased to 80kg - infants 10kg, and economy passengers 30kg.

Najib's entourage of six business class passengers of which two are platinum members, one infant, and 17 economy class passengers would add up to a total baggage allowance of 840kg.