HONG KONG — Macau voters have elected a young pro-democracy activist to the Chinese casino capital’s legislature, as opposition lawmakers expanded their presence at the expense of candidates linked to the gambling industry.

The results released early Monday are a surprising sign of faith in young people with progressive ideas among Macau’s notoriously apathetic electorate.

Official results showed that 26-year-old Sulu Sou won a seat in Sunday’s election for the city’s semi-democratic legislature, making him the city’s youngest-ever lawmaker, according to local news reports.

Sou’s party, the New Macau Association, favors full democracy for the 33-seat legislature, where only 14 seats are directly elected and the rest are filled by pro-establishment labor unions and special interest groups or appointed by the city’s Beijing-backed top leader. The party also aims to reinvigorate interest in politics among the former Portuguese colony’s younger generation.

Sou, who could not be reached for comment, joined three incumbent pro-democracy candidates who won re-election. Another surprise winner was newcomer Agnes Lam, a university professor seen as a centrist. There were few other changes to the rest of the directly elected seats, which remain dominated by pro-Beijing representatives.

Sou has done well in “projecting an image of freshness and youthfulness in Macau’s political landscape,” said Sonny Lo, a politics professor at HKU Space. Over the past five years, Sou “has been working very hard to raise all sorts of issues which were traditionally regarded as sensitive in Macau,” such as political reform. In 2014, he also helped lead the city’s biggest protest since its 1999 handover to China, which saw 20,000 people take to the streets to rally against a government plan to give civil servants lavish retirement benefits.

The vote also highlighted some lingering public discontent over the government’s hapless response to a powerful typhoon that battered Macau weeks earlier, flooding its old town, killing 10 and leaving hundreds more injured.

Macau’s economy has boomed over the past decade as supercharged growth in the casino industry transformed the enclave from a seedy and corrupt backwater into a glitzy gambling powerhouse.

But Lo, who calculated that gambling industry-related candidates lost two seats in direct voting, said the results indicate “many younger voters believe that the legislative assembly should not be dominated by the casino-related forces.”

Results showed 57.2 percent of registered voters cast ballots in Macau, a semiautonomous Chinese city with a population of 636,000 that is an hour by ferry from Hong Kong.