Security forces physically ejected Hungarian opposition lawmakers from the headquarters of the Hungarian state broadcaster MTVA in Budapest in the early hours of Monday morning.

In a video posted on opposition lawmaker Bernadett Szel's Facebook page, she and fellow independent opposition lawmaker Akos Hadhazy are seen being pushed out of the MTVA headquarters by security guards.

A group of 10 lawmakers had entered the building, insisting on the right to read five demands live on air. The demands included the revocation of the new labor law, passed last week in parliament, which gives employers the right to request up to 400 hours of overtime annually, without payment settlement for up to three years.

The right-wing government of Prime Minister Viktor Orban says the law will help relieve the current shortage of labor in Hungary's booming manufacturing sector, and allow workers to earn more.

But the "slavery law," as critics have dubbed it, has sparked widespread protests among unions and opposition parties across the political spectrum.

Thousands braved subzero temperatures to go to the parliament in Budapest on Sunday, where speakers condemned the new law while the angry crowd chanted slogans such as "We've had enough".

As protesters dispersed on Sunday evening, an estimated 2,000 - 3,000 moved on to the state broadcaster, shouting anti-government slogans.

After the delegation of opposition MPs were allowed into the building to negotiate their demands, riot police guarding the headquarters outside used pepper spray on at least two occasions to repel protesters trying to break through the cordon.

Hadhazy read the demands to camera in the early hours of Monday, but it is not clear whether these were broadcast.

Protesters returned to the MTVA headquarters on Monday morning and vowed to continue the struggle.

Balazs Hidveghi, communications director of the governing Fidesz party, on Monday denounced the lawmakers' actions, saying, any attempt by politicians to "forcefully interfere" with operations of the public media is unacceptable. He accused the lawmakers of setting off a fire alarm and "violently attacking public TV staff."

Video broadcast by the protesters showed Hadhazy trying to evade security staff in the MTVA building and enter the studio section by climbing the banisters of a staircase. Security staff prevented Hadhazy's progress.