Qatari authorities say they arrested a German television crew for filming a documentary without permission, not because of corruption allegations or the building conditions for the 2022 World Cup it exposed.

"Sold Football - Sepp Blatter and the power of FIFA" was screened on Monday by German broadcaster ARD and highlights harsh conditions facing migrant workers building stadiums in Qatar.

In the documentary, a member of FIFA's executive committee admits a business deal around the time the World Cup was awarded with leading companies in Qatar and Russia, which will host the 2018 tournament.

It has emerged that while shooting, the crew were taken into custody for 14 hours in Qatar and interrogated by state security officials.

The Germans were only allowed to leave the country five days later without their filming equipment, laptops and mobile phones which were confiscated.

All their electronic devices were sent back to Germany separately, but arrived partially damaged after a four-week delay and all data had been deleted, according to their claims.

"Now it's public. We got arrested in Qatar, interrogated by the police and the intelligence service. Not allowed to leave the country for days," ARD reporter Florian Bauer wrote on Twitter on Monday night.

ARD say the reporting team had failed to obtain permission to film through the correct channels and various requests for interviews had not been answered.

But authorities in Qatar say the arrests were made because the crew filmed without permits and they claim a second German television crew -- who had permission -- encountered no such problems.

"The journalist and the film crew concerned were not arrested as a result of reporting on allegations surrounding the 2022 FIFA World Cup Qatar or FIFA," said a statement from Qatar's Supreme Committee for Delivery & Legacy (SC).

"Any media outlet wishing to film in Qatar requires a film permit to do so, as is common in many countries.

"Any working journalist who has visited Qatar will be aware of this process and understand filming in specific locations without permission runs the risk of legal repercussions.

"The journalist in question has visited Qatar several times before.

"Furthermore, during the same period a second film crew from the same German network also visited Qatar, gaining access to numerous locations and stakeholders throughout the country.

"To our knowledge they encountered no such problems."