Budapest: Opponents of Hungary's far-right prime minister, Viktor Orban, have demonstrated for the fourth day in the past five, in what has become one of the most sustained displays of street opposition to Orban since he entered office eight years ago.

The protests began on Wednesday as a reaction to two new laws: one that forces employees to work up to 400 hours of overtime a year, and a second that created a parallel judicial system that will severely undermine judicial independence.

By Sunday, the demonstrations had become a catchall protest against many aspects of Orban's increasingly autocratic governance.

The protesters, whose numbers peaked at an estimated 15,000 on Sunday, were relatively small, given that Orban was re-elected in April with nearly 50 per cent of the vote.