Under the new rules governing the tax, KATA taxpayers who invoice a single company will have to pay a 40% tax on income above 3 million forints (EUR 8,500).

The flat monthly 50,000 forint payment will still apply to those who invoice multiple entities as long as annual income does not exceed 12 million forints.

Áder said he had received calls from three professional organisations over the past several days to send the bill back to parliament on the ground that the changes made to the KATA tax were too harsh.

The amendments made to the tax will close certain loopholes without affecting the more than 300,000 KATA taxpayers, Áder said, insisting that they would not have to pay higher taxes.