Security guards ejected two independent lawmakers from Hungary's state television building on Monday after they tried to read out a petition, a day after police used tear gas against pro-democracy protesters in Budapest.

The two lawmakers were among about a dozen members of parliament who spent the night in the state television MTVA's building demonstrating against the policies of Hungary's right-wing Prime Minister Viktor Orban.

Sunday's protest, that brought around 10,000 people out onto the streets of Budapest, was the fourth and biggest against Orban in a week, effectively uniting the fragmented opposition in action against his government for the first time since 2010 when he came to power. More demonstrations expected in Monday evening.

"Lawmakers being thrown out using physical force is unlawful and unjustified," said Daniel Dobrentey, a lawyer at the Hungarian Civil Liberties Union (TASZ).

The protests, which have been organized on Facebook and attracted many young people and students, were to resume on Monday at 1700 GMT.

In their petition, the opposition lawmakers backed the protesters in calling for the withdrawal of a new labor law, for independent public media and courts and for Hungary to join the European Union's prosecutors' office.

A spokesman for Orban's ruling Fidesz party criticized the lawmakers for going to the state TV building and said they were abusing their parliamentary powers by seeking to "meddle in editorial operations."

Independent lawmaker Bernadett Szel posted video footage on her Facebook page that showed the security guards tussling with her fellow-MP Akos Hadhazy and throwing him out of the building. Szel said she had also been ejected.

"We wanted to have our petition read out," she said in the video.

Visibly shocked by their treatment, the two MPs immediately filed a complaint with police stationed in front of the building.

They said that as MPs they had a right to be on the premises of a public establishment and to airtime on the public broadcaster.

"This is not a private television station for Fidesz," the party of right-wing nationalist Prime Minister Viktor Orban, "but the television of the Hungarian people, financed by the people's taxes," said the MPs, who streamed the altercation live on Facebook.

Public television has been turned into a government mouthpiece, protesters said Sunday night, demanding "free public media."

New level

On Sunday, some 10,000 protesters took part in a march dubbed "Merry Xmas Mr. Prime Minister" against what they see as the increasingly authoritarian rule of Orban.

The protests pose no immediate threat to Orban, who has strong core support which helped him return to power again in April.

But Peter Kreko, director of the think tank, Political Capital, said the government's reaction to the protests showed "short-sighted arrogance."

He said while it was unclear who ordered the MPs to be thrown out of the public TV building by security staff, the reaction of Fidesz to the events showed a new level in Orban's policy.

"This is stepping up one level in the regime's authoritarian logic," Kreko said.

The labor legislation relaxes restrictions on overtime work. It has sparked almost daily protests -- backed by the opposition -- since it was adopted on Wednesday.

The petition also demands the annulment of another controversial law adopted on the same day, which paves the way for new "administrative courts" to oversee cases concerning matters such as public procurement or electoral disputes.

Justice Minister Laszlo Trocsanyi, a close Orban ally, would oversee the courts. That has prompted warnings the premier could have near-total political influence over the judicial system.

After the TV station refused to broadcast the petition on Sunday evening, some protestors threw smoke bombs at police, who responded with tear gas.

On Monday morning, about ten MPs from various opposition parties said they had managed to evade MTVA's security guards and were still inside the building, pressing staff to read out the petition.

Hadhazy announced that another demonstration would take place at 18:00 local time (17:00 GMT) in front of the MTVA building under the slogan: "If they throw us out the door, we'll come back in through the window".

The wave of anti-government protests in recent days has seen opposition parties from across the spectrum joining forces against Orban's government in a way not seen in recent years in Hungary.

Unions have also backed the demonstrations against the reforms, which hike the annual overtime hours that employers can demand from 250 to 400 hours and allow payment to be delayed by up to three years.

The government says the changes are needed by employers short of manpower and will benefit those wanting to work extra hours.

Over the weekend protestors also gathered in other parts of the country. In the third-biggest city Szeged the socialist mayor has called on businesses not to comply with the new overtime law.