While Austria had refused, the two governments did reach an accord last summer that Austria would clamp down on excessive pollution by the factory and would notify Hungary of any breaches. Hungary says Austria has failed to do this.

"I will negotiate with my Austrian counterpart that the leather factory in Wollsdorf (also reduce pollution)," Fodor said, adding that two other factories along the river, called Raab in Austria, had already cut pollution below the limit.

He made the comments in a statement after a visit to the river at the town of Szentgotthard near Hungary's border with Austria.

He said recent samples from the river showed the amount of a leather tanning material, which covers the water with white foam, has increased to three times the reading five years ago.

Austria has said the leather factory's water-cleaning facilities were state of the art and the river's water quality met existing standards.