Viktor Orban said refugees had rebelled against the country's laws and had failed to co-operate with authorities in recent days.

Thousands of refugees have been entering Hungary from its southern neighbour Serbia as they try to make their way towards western European countries, including Germany.

It comes as Austria closes part of the A4 motorway near the Hungarian border for security reasons as scores of refugees tried to reach Vienna on foot.

Reporters estimate 1,000 people pushed through police cordons to make the 64km trip on foot on Friday as Austria's railway company, OeBB, stopped its service from and to Hungary due to overcrowding.

Services will remain suspended through the weekend, the company said in a statement.

"This decision to stop traffic to and from Hungary made it possible to stabilise the situation in Vienna's large train stations. This is important to keep train services running," OeBB said.

Packed trains have been taking thousands of refugees and refugees from the Hungarian border to Vienna for days with most heading on to Germany and other West European countries.

Some 8,000 people crossed the border into Austria on Thursday and 3,600 had already made their way across since midnight. 

Police spokesman Gerhard Koller said 1,500 people had spent the night outdoors.

It comes as Hungarian police launched an investigation into a video showing police in surgical masks throwing out packs of sandwiches to refugees clamouring for food at a reception centre in Roszke on Hungary's southern border with Serbia.

Spritzendorfer-Ehrenhauser, who was visiting the camp with the Hungarian Red Cross, took the footage at dinner time.

"There were maybe 100 people trying to catch these plastic bags with sausages... They were not able to organise a camp and treat them like human beings."

A government spokesman Zoltan Kovacs said the footage showed policemen "trying to maintain order among those who are unable to line up for food."