The United Nations refugee agency (UNHCR) has called on Prime Minister Viktor Orban's government to scrap a recent hardening of the Hungarian asylum system, saying some provisions could violate international laws.
A Hungarian government spokesman declined to comment immediately.
Hungary last month shut so-called migrant transit zones on its borders, freeing some 300 refugees from prison-like conditions while at the same time tightening the regulations and effectively barring future asylum applicants.
The new rules require asylum seekers to submit applications at consulates in neighboring countries rather than at the Hungarian border.
"This may expose asylum-seekers to the risk of refoulement and ill-treatment which would amount to a violation of the 1951 Refugee Convention and other international and regional human rights instruments to which Hungary is a State Party," the UNHCR said in a statement on June 29.
"Effective access to territory is an essential pre-condition to be able to exercise the right to seek asylum," the statement said.
Human rights groups have already voiced concern that the newly tightened rules would make it even harder for refugees to gain asylum in the EU via Hungary.
UNHCR urged Budapest to withdraw the act and bring its asylum system in line with international human rights laws as well as European Union law.
At the peak of European Union's 2015 migrant crisis, Orban, one of the fiercest opponents of immigration, ordered Hungary's southern border to be sealed, blocking a route for hundreds of thousands of migrants.
UN Urges Hungary To Repeal Tightened Asylum Rules