New rules mean companies can demand up to 400 hours of overtime a year and delay payment for it for three years.

Police used tear gas against crowds on the steps of the parliament building on Wednesday night as crowds gathered.

Opposition politicians had created chaos inside, blocking stairways and blowing whistles to disrupt the votes.

They were also angry over a second vote to create a new system of administrative courts controlled by the minister of justice, which critics fear will not be independent.

The parliamentary speaker, unable to reach his podium, was forced to open the session from the floor instead. Despite the disruption, Prime Minister Viktor Orban's overwhelming majority in parliament pushed the change through.

Hundreds of protesters - one estimate suggested up to 2,000 - gathered outside the building late on Wednesday to protest against the "slave labour" amendment, while hundreds of police protected the entrance.

Police in riot gear, forming a human barrier, used tear gas against the crowd when a small number of protesters attempted to push their way past.

A small group of protesters set fire to some street furniture and refuse

It followed a weekend protest over the proposed change, where crowds gathered calling for higher minimum wages, rather than an increase in overtime.

In Hungary, the law previously allowed for companies to demand a maximum of 250 hours of overtime in a given year.

But for someone who works eight-hour days, the new amount of 400 hours is the equivalent of an hour of extra labour every day, an extra day's work every week, or 50 extra days each year.

Mr Orban's government, however, argues that the labour reform will benefit workers as well as companies who need to fill a labour shortage.

"We have to remove bureaucratic rules so that those who want to work and earn more can do so," he said on Tuesday before the bill passed.

Neither the country's trade unions nor the political opposition agree.

The judicial reform is also seen as controversial by many of the prime minister's opponents.

Since coming to power, Mr Orban has remained popular by adopting a strong anti-migrant stance and championing national sovereignty.

A report from the European Union into its member state accuses his government of attacks on the media, minorities and the rule of law.

The European Parliament took the unprecedented step of voting to pursue disciplinary action against Hungary, citing - among other things - concerns over pressure being placed on the courts, widespread corruption and the independence of the electoral system.

Critics of the new administrative court fear that it may continue that trend.

The new courts will be supervised by Mr Orban's justice minister, who will appoint its judges. Its remit - to deal with public administration issues - will likely cover areas including elections and corruption.

It will run in parallel to the existing court system, but with no oversight by it.

Mr Orban, however, has been defiant in the face of increasing isolation in Brussels, labelling the EU's actions against him as "blackmail" and an "insult" to his country.