Bangladeshi authorities have launched an investigation after a pornographic film was aired on a large display screen at the country's main airport, a magistrate said.

Hundreds of travellers and waiting friends and relatives at the main terminal of the Shahjalal International Airport were shocked as the film was aired for five minutes on Friday morning, magistrate Siddiqa Akhter said.

The display screen usually shows recorded documentaries about the culture and geography of Bangladesh, a conservative Muslim country.

"The operator has been jailed instantly for two months," Mr Akhter said.

"We have also summoned the owners of the cable firm to investigate the incident.

"We have to find out whether any criminal intent was involved."

Every day, thousands of people throng the terminal to receive or send off their relatives.

- AFP