Armenians have voted in parliamentary elections triggered years ahead of schedule by the reformist leader Nikol Pashinyan, who is aiming to cement his political authority.

The 43-year-old former journalist became prime minister in May after spearheading weeks of peaceful anti-government rallies that ousted veteran leader Serzh Sargsyan. Parliamentary elections had not been scheduled to be held until 2022.

He has pledged to root out endemic corruption and address widespread poverty, earning him supporters in the impoverished, landlocked nation of about 3 million people.

“After the elections, we will be developing Armenian democracy and make an economic revolution happen,” Pashinyan told journalists after casting his ballot on Sunday, pledging to “hold free, fair, and transparent elections”.

Pashinyan’s reform drive had been stalled for months by opposition from Sargsyan’s ruling Republican party, which dominated the national assembly until Pashinyan’s calculated resignation triggered parliament’s dissolution last month.

Acting prime minister Nikol Pashinyan casts his ballot. Photograph: Anadolu Agency/Getty Images

At a polling station in the centre of the capital, Yerevan, voters expressed optimism about the political change promised by Pashinyan and vented their anger at corrupt former officials.

“Thanks to the revolution, we will finally have fair elections,” 72-year-old pensioner Parzik Avetisyan told AFP. “I voted for the positive change promised by Nikol [Pashinyan],” he added.

Another voter, 52-year-old painter Garnik Arakelyan, said: “I want all those corrupt officials who for many years were robbing and humiliating people to be jailed.”

Pashinyan’s party is expected to get a majority in the new legislature, allowing him to push ahead with his campaign to reshape the South Caucasus nation’s political landscape and spark an “economic revolution”.

Last week, Pashinyan – who is acting prime minister – promised “the best elections Armenia has ever seen”, without ballot-stuffing or voter intimidation.

Analysts say Pashinyan sought new elections while he is at the peak of his popularity.

In September, his bloc had a landslide victory in municipal elections, winning more than 80% of the vote in Yerevan, where nearly 40% of the former Soviet republic’s population lives.

Nine political parties and two electoral blocs are competing for mandates in the 101-seat national assembly.