Neighbouring Austria meanwhile witnessed a new spike in numbers crossing from Hungary, with more than 3,000 people entering overnight.
The majority entering Hungary crossed the border near this flashpoint village, the scene of a number of scuffles between police and migrants in recent days.
The UN’s refugee agency on Tuesday warned that at least 42,000 migrants were expected to enter Hungary by next week, as they travel up from Greece via Macedonia and Serbia.
Most are from Syria, Afghanistan or Pakistan and want to continue their journey to Germany, where the government recently eased asylum restrictions for Syrians.
Between midnight (2200 GMT) and 3:00 am alone, more than 1,700 people crossed the border at Nickelsdorf in eastern Austria, police said.
Early this morning, there were around 2,800 people at Nickelsdorf, receiving food, temporary shelter and waiting for special buses and trains to take them to Vienna and beyond.
The situation was however calm and people were exhausted but very happy to be in Austria, said Christian Knopf, in charge of coordination.
At the weekend, Austria allowed some 15,000 to enter the country freely to help relieve a near-explosive situation in Hungary where 50,000 migrants arrived in August alone.
Chancellor Werner Faymann has said that border controls will return to normal but this has not yet happened. A government coordination meeting today was to discuss the next steps.
Austrian police said that those arriving had generally crossed into Hungary from Serbia less than 24 hours before, many taking trains to Budapest and then changing onto other trains to Hegyeshalom near the Austrian border.
Volunteers at the border said they are bracing for a renewed spike in numbers in the coming days as many migrants rush to enter Hungary before tough new laws there outlawing crossing the border come into force on September 15.
Hungary in late August completed a razor-wire barrier along its 175-kilometre border with Serbia which is however not proving to be much of a hindrance.
It is however also building a fence four metres high that it aims to complete by the end of October or early November, and the government wants to start deploying the army.
Police meanwhile announced they were letting refugees travel freely through Denmark without registering if they didn’t want to seek asylum there, allowing them to head to Sweden which is the preferred destination of many because of its more welcoming and generous asylum policy.
“We can’t hold foreigners who don’t want to seek asylum” in Denmark, national police chief Jens Henrik Hojbjerg said.
The police decision appeared to contradict the Danish political line.
Prime Minister Lars Lokke Rasmussen insisted on Monday that refugees arriving in Denmark ought to be registered and have their asylum requests processed there.
Train operator DSB said trains would be functioning normally today between Flensburg in northern Germany and Padborg in southwestern Denmark.
However, a busy ferry crossing in Rodby, around 135 kilometres south of Copenhagen, would remain closed to trains a day after 340 refugees refused to disembark from services arriving from Germany, Denmark’s southern neighbour, demanding to continue on to Sweden.
Many of the refugees refused to register with Danish authorities.
After lengthy negotiations, around 100 of them agreed to remain in Denmark and lodge their asylum requests there.
The 240 or so others were allowed to disembark late yesterday without police intervening.
“Where they have gone I don’t know. I think they were picked up by private cars or have taken taxis further away. We are no longer monitoring them,” police commissioner John Andersen told news agency Ritzau.
Sweden, one of many European countries struggling with the worst migration crisis since World War II, has become a top EU destination for refugees by issuing permanent residency to all Syrian asylum seekers.
In contrast, Denmark has sought to reduce the influx by issuing temporary residence permits, delaying family reunions and slashing benefits for newly arrived immigrants.
Ferry operator Scandlines announced that only passengers travelling by car would be let aboard ferries between Rodby and Puttgarden in Germany.
The ferries usually carry both cars, trains and passengers on foot.
Police had yesterday closed part of a motorway near Padborg for a few hours after around 300 refugees, including large numbers of women and children, set off on foot for Sweden.
The migrants had been housed in an old school building after arriving in the town but took to the road, saying they wanted to travel north to Sweden.
Some elderly migrants called off their 300-kilometre trek to Copenhagen, the jumping-off point for crossings by bus, train or car to Sweden.
Yesterday afternoon, the rest of the group left the motorway to spend the night in a local community centre.
According to Danish authorities, 3,200 refugees have arrived in Denmark since Sunday, of which 400 have sought asylum. — AFP