Protesters threw smoke grenades at police who responded with tear gas in Budapest on Sunday as thousands of people rallied against a new "slave law" passed by the government of conservative Prime Minister Viktor Orban.

More than 15,000 people joined the demonstration according to local reports. On Monday, the protests - the first since Mr Orban returned to power in 2018 - entered their fourth day.

The protests are led by unions and opposition parties outraged at reforms that hike the overtime hours employers can demand from 250 to 400 hours annually, and which also allow payment to be delayed by up to three years.

The government says the changes are needed by employers who find themselves short of manpower and will benefit people who want to work extra hours.

Sunday's protest finished at Parliament Square, where protesters chanting: "Orban get lost!" have been gathering since the law was adopted last week.

Protesters led by two opposition politicians later marched to Hungary's public television headquarters to read a petition but were refused access.