Hungary is to start building a new fence on the Serbian border in the spring to hold back an expected new surge of migrants.

Janos Lazar, Chief of Staff to Prime Minister Viktor Orban, said construction will begin as soon as the weather allows, amid fears hundreds of thousands of migrants could once again attempt to travel up through the Balkans in order to reach Western Europe.

AP reports the Hungarian government expects to spend around £104 million on the new fence, and will also set up shipping containers at key points along the border to help process any new arrivals. Asylum seekers will have to wait at these sites while their applications are processed.

Mr Lazar said the new fence would act as a “second line of defence”, and confirmed asylum seekers would not be free to roam to the country as happens in other European Union (EU) states.

Hungary has led Europe in protecting its borders amid the worse migrant crisis since the Second World War.

In 2015, thousands of migrants poured into the country, causing chaos at Budapest’s main train station after German Chancellor Angela Merkel announced her country would open its borders to them.

Her call led to over a million migrants travelling across Europe to Germany, eventually prompting the Hungarian government to build a border fence to stop the migrant flow.

The decision by Viktor Orban’s government was initially condemned by other European leaders, but by May 2016 it was clear the fence had slowed the flow of migrants through the country to a trickle.

The Hungarian government’s tough line on immigration has led to the ruling Fidesz party soaring in opinion polls, with one survey earlier this month giving the party 49 per cent, 30 points ahead of their nearest rivals.

The next election is due in spring 2018.