BUDAPEST — Opponents of Hungary’s far-right prime minister, Viktor Orban, demonstrated on Sunday for the fourth day in the past five, in what has become one of the most sustained displays of street opposition to Mr. 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 Mr. Orban’s increasingly autocratic governance.

The protesters, whose numbers peaked at an estimated 15,000 on Sunday, held relatively small events, given that Mr. Orban was re-elected in April with nearly 50 percent of the vote in an election that observers said was free but not fair.