Viktor Orban’s right-wing populist party has vowed to would crack down on organisations helping migrants and refugees, in an announcement made just a day after it won an overwhelming election victory.

The autocratic prime minister portrayed himself as the saviour of Hungary’s Christian culture against Muslim migration into Europe, an image which resonated with more than 2.5 million voters.

His Fidesz party won a two-thirds super majority in the country’s parliament, which would allow it and its small ally, the Christian democrats, to push through changes to constitutional laws.

It would also enable it to push through the so-called “Stop Soros” bill, said Janos Halasz, the party’s parliamentary spokesman.

Mr Orban has claimed the opposition is collaborating with the United Nations, the European Union and the wealthy philanthropist George Soros to turn Hungary into an “immigrant country.”

The draft law targeting advocates for refugees could come as soon as May, the party said.

It could make it hard for groups working with asylum-seekers to continue their activities in Hungary.

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The laws would force NGOs working with migrants and asylum seekers to get government permits, income received from abroad would be taxed by 25 per cent, advocacy groups could be banned from going closer than 8km (5 miles) from Hungary’s borders - where asylum-seekers file claims - and foreigners without authorization to help refugees could be banned from Hungary.

Their activity would have to be approved by the interior minister, who could deny permission if he saw a “national security risk”.

The Hungarian Helsinki Committee, which provides legal help for asylum-seekers, said it would not let the election results derail its mission.

The committee receives support from Mr Soros’s Open Society Foundations and is frequently identified by the government as one of the “foreign agents” supposedly working against Hungary’s national interests.

“Our association will continue its activities for as long as people in dire straits ask us for help,” the group said. “We are the same age as Hungarian democracy, established in 1989, of which there is less and less left.”

The Helsinki Committee said it was clear Fidesz “considers its power interests more important than the values of the state of law and democracy, human rights and the Constitution.”

Refugee crisis - in pictures Show all 27 1 /27 Refugee crisis - in pictures Refugee crisis - in pictures A child looks through the fence at the Moria detention camp for migrants and refugees at the island of Lesbos on May 24, 2016. AFP/Getty Images Refugee crisis - in pictures Ahmad Zarour, 32, from Syria, reacts after his rescue by MOAS (Migrant Offshore Aid Station) while attempting to reach the Greek island of Agathonisi, Dodecanese, southeastern Agean Sea Refugee crisis - in pictures Syrian migrants holding life vests gather onto a pebble beach in the Yesil liman district of Canakkale, northwestern Turkey, after being stopped by Turkish police in their attempt to reach the Greek island of Lesbos on 29 January 2016. Getty Images Refugee crisis - in pictures Refugees flash the 'V for victory' sign during a demonstration as they block the Greek-Macedonian border Refugee crisis - in pictures Migrants have been braving sub zero temperatures as they cross the border from Macedonia into Serbia. Refugee crisis - in pictures A sinking boat is seen behind a Turkish gendarme off the coast of Canakkale's Bademli district on January 30, 2016. At least 33 migrants drowned on January 30 when their boat sank in the Aegean Sea while trying to cross from Turkey to Greece. Getty Images Refugee crisis - in pictures A general view of a shelter for migrants inside a hangar of the former Tempelhof airport in Berlin, Germany Refugee crisis - in pictures Refugees protest behind a fence against restrictions limiting passage at the Greek-Macedonian border, near Gevgelija. Since last week, Macedonia has restricted passage to northern Europe to only Syrians, Iraqis and Afghans who are considered war refugees. All other nationalities are deemed economic migrants and told to turn back. Macedonia has finished building a fence on its frontier with Greece becoming the latest country in Europe to build a border barrier aimed at checking the flow of refugees Refugee crisis - in pictures A father and his child wait after being caught by Turkish gendarme on 27 January 2016 at Canakkale's Kucukkuyu district Refugee crisis - in pictures Migrants make hand signals as they arrive into the southern Spanish port of Malaga on 27 January, 2016 after an inflatable boat carrying 55 Africans, seven of them women and six chidren, was rescued by the Spanish coast guard off the Spanish coast. Refugee crisis - in pictures A refugee holds two children as dozens arrive on an overcrowded boat on the Greek island of Lesbos Refugee crisis - in pictures A child, covered by emergency blankets, reacts as she arrives, with other refugees and migrants, on the Greek island of Lesbos, At least five migrants including three children, died after four boats sank between Turkey and Greece, as rescue workers searched the sea for dozens more, the Greek coastguard said Refugee crisis - in pictures Migrants wait under outside the Moria registration camp on the Lesbos. Over 400,000 people have landed on Greek islands from neighbouring Turkey since the beginning of the year Refugee crisis - in pictures The bodies of Christian refugees are buried separately from Muslim refugees at the Agios Panteleimonas cemetery in Mytilene, Lesbos Refugee crisis - in pictures Macedonian police officers control a crowd of refugees as they prepare to enter a camp after crossing the Greek border into Macedonia near Gevgelija Getty Images Refugee crisis - in pictures A refugee tries to force the entry to a camp as Macedonian police officers control a crowd after crossing the Greek border into Macedonia near Gevgelija Getty Images Refugee crisis - in pictures Refugees are seen aboard a Turkish fishing boat as they arrive on the Greek island of Lesbos after crossing a part of the Aegean Sea from the Turkish coast to Lesbos Reuters Refugee crisis - in pictures An elderly woman sings a lullaby to baby on a beach after arriving with other refugees on the Greek island of Lesbos after crossing the Aegean sea from Turkey Getty Images Refugee crisis - in pictures A man collapses as refugees make land from an overloaded rubber dinghy after crossing the Aegean see from Turkey, at the island of Lesbos EPA Refugee crisis - in pictures A girl reacts as refugees arrive by boat on the Greek island of Lesbos after crossing the Aegean sea from Turkey Getty Images Refugee crisis - in pictures Refugees make a show of hands as they queue after crossing the Greek border into Macedonia near Gevgelija Getty Images Refugee crisis - in pictures People help a wheelchair user board a train with others, heading towards Serbia, at the transit camp for refugees near the southern Macedonian town of Gevgelija AP Refugee crisis - in pictures Refugees board a train, after crossing the Greek-Macedonian border, near Gevgelija. Macedonia is a key transit country in the Balkans migration route into the EU, with thousands of asylum seekers - many of them from Syria, Afghanistan, Iraq and Somalia - entering the country every day Getty Images Refugee crisis - in pictures An aerial picture shows the "New Jungle" refugee camp where some 3,500 people live while they attempt to enter Britain, near the port of Calais, northern France Getty Images Refugee crisis - in pictures A Syrian girl reacts as she helped by a volunteer upon her arrival from Turkey on the Greek island of Lesbos, after having crossed the Aegean Sea EPA Refugee crisis - in pictures Refugees arrive by boat on the Greek island of Lesbos after crossing the Aegean sea from Turkey Getty Images Refugee crisis - in pictures Beds ready for use for migrants and refugees are prepared at a processing center on January 27, 2016 in Passau, Germany. The flow of migrants arriving in Passau has dropped to between 500 and 1,000 per day, down significantly from last November, when in the same region up to 6,000 migrants were arriving daily.

Before the election, Mr Orban’s government had warned Hungary would descend into chaos should it become an “immigrant country” like France or Belgium, with funds meant for Hungarian families or the country’s underprivileged Roma minority diverted to migrants.

The government said the presence of migrants would weaken Hungary’s security and increase its risk of terrorism.

He also warned the migrants would halt Hungary’s economic development, would weaken government support for rural areas, would threaten the safety of women and girls, and would turn the capital Budapest into an “unrecognizable” city.

“If the dam bursts, if the borders are opened, if immigrants set foot in Hungary, there will be no going back,” Mr Orban had said at a final campaign rally on Friday.

Viktor Orban, Hungary's prime minister, addresses supporters after the announcement of the partial results of parliamentary election in Budapest, Hungary (Laszlo Balogh/Getty Images)

A spokesman the European Commission’s president, Jean-Claude Juncker, would write to Mr Orban to congratulate him on his victory but emphasise defending democracy and values was the common duty of all member states with no exception.

Donald Tusk, president of the European Council, said in a statement: “During your renewed term as prime minister I count on you to play a constructive role in maintaining our unity in the EU.”

Angela Merkel, the German chancellor, congratulated Mr Orban, a spokesman said, adding she would work with his new government despite their differences on migration.

The first leader to congratulate Mr Orban was Marine Le Pen, who heads France’s National Front.

Poland’s deputy foreign minister and envoy to the EU, Konrad Szymanski, hailed his victory as “a confirmation of Central Europe’s emancipation policy”.

Before the election, Hungary had already signalled it would be looking to expand co-operation on migrant policy with neighbouring Austria, the only country in Western Europe with a far-right group in government, as well as Italy, where the centre-left Democratic Party lost to anti-establishment and right-wing parties which campaigned hard against immigration.

“Orban is implementing sustainable and correct policies for the people of his country... Hungary’s voters have rewarded that once again,” Austria’s vice chancellor and leader of the far-right Freedom Party, Heinz-Christian Strache, said.