AFP/ Budapest

Hungary's justice minister on Wednesday dismissed concerns that a new law criminalising illegal border crossings, part of a raft of tough new anti-migrant laws, could violate the UN Convention on Refugees.

"The UN Convention -- Article 31 -- clearly says that illegal border crossing is not allowed if the person is entering from a country where his life is not in danger," Laszlo Trocsanyi told reporters.

Since the migrants were crossing from Serbia, he said the convention did not apply.

New laws due to come into force on September 15 mean that crossing the Hungarian border without legal papers will be treated as a crime, leading to deportation or even jail.

"If a person can prove he was persecuted in Serbia, then it's not a crime," said Trocsanyi.

The UN refugee agency (UNHCR) said Tuesday that under Article 51 of the UN Refugee Convention, no one can be prosecuted for illegal entry if they are seeking asylum. 

Some 85 percent of those in the current migration flow into Europe are considered refugees because they have fled wars in Syria, Iraq and Afghanistan, UNHCR Europe director Vincent Cochetel told a press conference in Budapest.

"We will have to see whether the Hungarian courts apply international standards, and if they don't, those matters will be referred to the European Court of Human Rights," he said.

The new laws in Hungary also allow for new "transit zones" to hold asylum seekers while their applications are being processed, and allow for the deployment of soldiers to reinforce newly-created "border hunter" patrols.