Home Minister Ahmad Zahid Hamidi has hit out at immigration officers at KLIA over its passport gaffe in allowing imposters with European identities to board missing Malaysia Airlines (MAS) flight MH370, despite having Asian features.

"I am still puzzled how come (immigration officers) cannot think, an Italian and Austrian (passengers) but with Asian facial features," he was quoted saying by national news agency Bernama yesterday.

As such, Zahid said, a detailed probe would be conducted, with special attention on the department's KL International Airport (KLIA) branch.

"We will conduct an internal probe, particularly on the officers who were on duty at the KLIA Immigration counter during flight MH370,” he is quoted as saying.

Immigration Department director-general Aloyah Mamat will lead the investigating team.

Following the release of the passenger list manifest, it was discovered that Italian Luigi Maraldi, and Austrian Christian Kozel were reported to be alive and well as the duo never boarded the flight.

Both had claimed they previously reported their passports stolen in Thailand, giving rise to fear of a terrorist link in the disappearance of MH370.

The flight disappeared not long after taking off from KLIA at 12.41am on Saturday, en route to Beijing with 227 passengers, including two infants, and 12 crew members on board.

Even Interpol chided both Malaysia and MAS for failing to make use of its database on stolen passports, as it stated that both passports in question are listed on its database.

According to Bernama , Zahid said no conclusion could be made on the matter as investigations only began once the actual passport holders claimed that their passports were stolen.

Zahid said it was difficult to determine the authenticity of international passports as unlike Malaysia, not all countries used the biometric system and bar code.