Austria has protested to Hungary after Viktor Orban's radical rightwing regime – which has made fighting irregular migration a key part of its domestic and foreign policy – began releasing human traffickers early, citing the high costs and the overcrowded jails.

Hungary's ambassador in Vienna was summoned by Foreign Minister Alexander Schallenberg (OVP) to demand clarification from Budapest after the government began to let convicted human traffickers leave prison.

"In the past few days, there had been disturbing media reports that Hungary apparently wants to release hundreds of convicted human traffickers", Schallenberg was quoted as saying by local news agency APA. "We think this is an entirely wrong signal,"  he added.

The Austrian foreign minister already discussed the issue with his Hungarian counterpart on Sunday, after which the Austrian government put in place stricter controls at the Austrian-Hungarian border. Budapest's argument contradicts the "seemingly clear line" of Hungary's past line on the issue of human trafficking, he added.

The campaign against irregular migration has been one of the cornerstones of Viktor Orban’s radical rightwing government since the migrant crisis in 2015. The Hungarian cabinet has blamed the EU leaders for inviting refugees to come to the continent.

At home Orban's regime has put in place some of the toughest policies against traffickers.  Hungarian criminal law provides for long prison sentences of two to 20 years for the crime. The EU’s highest court in 2021 ruled that Hungary's law criminalising support for asylum seekers and limiting the right to asylum violated EU law.

There are currently more than 2,000 foreigners serving prison sentences in Hungary, most of them convicted of human trafficking.

Hungarian Foreign Minister Peter Szijjarto, addressing a news briefing on Monday, defended the government’s move, saying it was a "sovereign Hungarian decision". Head of the Prime Minister's Office Gergely Gulyas earlier justified the step by saying that the incarceration of foreign criminals would be too expensive.

After the traffickers are released, a government decree stipulates that those convicted have 72 hours to leave the country, but there is no oversight or monitoring.

Austria is a prime destination for smuggled migrants travelling through Hungary – which is the most eastern part of the Schengen zone – on the Balkan route into the EU.

Despite the wire fence erected on the Hungarian-Serbian border in 2015, some 49,000 border violators and 387 human smugglers have been stopped in Hungary so far this year, according to Orban's chief domestic security advisor. Gyorgy Bakondi told public radio last week that migrants and human smugglers had kept Hungary's borders under significant pressure.

On Monday, Austrian Interior Minister Gerhard Karner (OVP) contacted his Hungarian counterpart and announced intensified border controls.

Austrian parties from all sides condemned Hungary’s move. Even FPO leader Herbert Kickl spoke out against the measure. The 54-year radical right-wing leader had earlier praised Hungary’s asylum policy, most recently at the CPAC gathering earlier this month.