Free Democrat (FDP) deputy parliamentary leader Patrick Döring told daily Bild the tax needed an overhaul. It was not fair, he said, that ordinary people going on holiday had to fork out extra charges while private jets got to avoid the tax.

He also demanded that business travellers and the wealthy pay a fairer share of the burden.

“First class travellers must pay more,” he said. “This way, the charge for the ordinary passenger can clearly be lowered.”

Under the present plan, passengers leaving German airports would pay a flat rate of €13 for short flights and €26 for long-haul flights. Transit passengers, freight, military flights and private jets are all exempt.

Chancellor Merkel’s centre-right coalition announced the charges just over a month ago as part of its effort would slash €80 billion from the budget by 2014. The airport tax would aim to raise €1 billion a year to funnel into the government’s severely drained coffers.

Döring’s criticism is the latest in a series of public rows between Merkel’s conservative Christian Democrats and their junior coalition partners, the FDP, with many of the disagreements centring on tax policy.