Germany faced off against the fiercest critics of its open-door refugee stance within the EU on Friday, as disturbing footage emerged of the way people were being treated inside one of Hungary's main migrant camps.

German foreign minister Frank-Walter Steinmeier was meeting his counterparts from the Czech Republic, Hungary, Poland, and Slovakia in Prague, with Europe bitterly split on how to deal with the massive flow of people crossing its borders.

With Hungary sending more troops to its frontier Friday where it is rushing up a four-metre high fence, Germany insisted an emergency EU plan to distribute migrants was just "a drop in the ocean" as eastern member states fiercely resist Berlin's push for permanent binding quotas.

"The distribution of 160,000 refugees across Europe is a first step, if one wants to be polite," said Germany's Deputy Chancellor Sigmar Gabriel. "It's a drop in the ocean."

As a record number of refugees fleeing wars in Syria and Iraq crossed Hungary's border Thursday, disturbing images from inside its controversial Roszke holding camp showed showed families being fed "like animals in a pen", with women and children caught in a scrum of hungry people frantically trying to catch sandwiches being thrown to them by police.

"It was inhumane and it really speaks for these people that they didn't fight over the food despite being clearly very hungry," said Austrian volunteer Michaela Spritzendorfer, who filmed the scenes.

They raise further questions about how refugees are being treated in Hungary, where harsh new laws to jail migrants for crossing its borders -- which were strongly criticised by the UN's refugee agency -- are due to come into force on Tuesday.

The images came as a Hungarian camerawoman who caused global outrage after being caught on film tripping and kicking refugees, including children, as they fled police said she had "panicked".

"I'm not a heartless, child-kicking racist camera-person," said Petra Laszlo, who was sacked by N1TV, an Internet-based television station close to Hungary's far-right Jobbik party, after the footage went viral.

The numbers of migrants streaming through the Balkans into Hungary on Thursday was the highest yet recorded, many braving police truncheons and torrential rain in their desperate attempt to reach Western Europe.

The surge, which Hungarian police said saw 3,321 people enter the country in just 24 hours, forced Austria's train operator to suspend services with Hungary due to "massive overcrowding".

Many are hurrying to cross the border before Hungary brings in tough new anti-migrant laws on Tuesday.

Others, fleeing war and poverty in the Middle East, Afghanistan or Pakistan, have endured treacherous and often deadly sea journeys across the Mediterranean to reach European soil.

Some 22,500 refugees and migrants on the Greek island of Lesbos have been registered by officials since Monday evening, according to police, many of them Syrian refugees setting sail from Turkey.

The European Union is bitterly divided over how to cope with the biggest migrant crisis in seven decades, with transit countries on the front line taking a tough stance while Western Europe has thrown open its doors.

Hungary has stirred anger with its heavy-handed tactics but its stance on quotas was echoed by its neighbours.

"It is inappropriate to talk about mandatory quotas, calculated on an extremely bureaucratic basis, almost like an accountancy exercise I might say, without consulting member states," said Romania President Klaus Iohannis.

His views chimed with those of Slovakian Prime Minister Robert Fico, who said Wednesday he did not "want to wake up one day and have 50,000 people here about whom we know nothing".

Juncker's proposals include a possible revision of the EU's much-criticised Dublin Treaty, under which asylum claims must be processed by the first country where refugees arrive.

EU lawmakers called for an international conference on migration bringing together the United States, United Nations and Arab countries.

Facing criticism that his government has been too slow to help, US President Barack Obama pledged to admit at least 10,000 Syrian refugees in the year starting October 1.

Spokesman Josh Earnest said Obama had ordered staff to "scale up" the number after over 62,000 Americans signed a petition calling on Washington to take in more people.

Meanwhile on Lesbos the boats kept arriving, with hundreds making a gruelling 50-60 kilometre (30-40 miles) walk from their landing place to the main town to be registered.

"We have been walking for four hours. There is no bus, no taxi, no water, no anything," said Mohammed Yassin al-Jahabra, a 23-year-old English literature student.

Thousands of people have been forced to camp on the streets in squalid conditions, and there were repeated clashes as riot police struggled to control huge crowds pressing forward to get on board ferries.