Preliminary results are expected several hours later. "Opposition politicians are right to be glad about high turnout, but it does not mean that anything has been decided".
While Fidesz led all opinion polls before the vote, there is a small chance that the fragmented opposition could strip Fidesz of its parliamentary majority if voters frustrated with Orban's policies choose tactical voting in the 106 constituencies.
Boros said in a tweet: "The Hungarian political landscape will dramatically change today".
Orban is seeking his third consecutive term and fourth overall and his campaign has been almost exclusively about opposing migration.
Hungary's parliamentary election on Sunday could produce the highest turnout on record, ruling Fidesz party parliamentary group leader Gergely Gulyas said, adding that it would give strong legitimacy to the next parliament.
While voters were no longer allowed to join queues at polling stations as of 1700 GMT, those already in line will be allowed to cast their ballots, a process that can take hours at the busiest polling stations.
As of a 8:45 p.m., most polling places had been closed, but one Budapest location still had 2,500 people waiting in line, according to Hungary's National Election Office.
'Today will decide whether Hungary becomes an emigrant country or not - and I wouldn't like Hungary to be an emigrant country, ' Mr Vona said.
Japan anime giant Isao Takahata dead at 82
Isao Takahata and Hayao Miyazaki, together had created commendable artistic works that deal with pain, despair and happiness. With Miyazaki, he co-founded in 1985 the Japanese animation Studio Ghibli , which went on to produce several blockbusters.
In last elections of 2014, Orban's coalition Fidesz-KDNP won 133 seats, securing two thirds of the parliament, also known as a super majority.
In the past few years, Vona, who has been party chairman since 2006, has pushed the party to abandon its frequently anti-Roma and anti-Semitic views and toward more a mainstream conservative direction. In Hodmezovasarhely, a Fidesz stronghold in southeastern Hungary, voters complaining of graft, cronyism, and intimidation elected an independent in a February mayoral election for the first time in two decades.
'We are celebrating democracy and it seems like this feast will be lovely because many of us are taking part, ' said Gergely Karacsony, the leading candidate of the left-wing Socialist and Dialogue parties.
Voters in Hungary are going to the polls in a general election on Sunday.
Orban told reporters after casting his ballot that he is fighting for the future of his beloved country.
The PM and his wife Aniko Levai were pictured voting at a school in Budapest this morning, while Hungarian citizens in London were seen queuing in the rain to cast their ballots.
Orban claims that the opposition - collaborating with the United Nations, the European Union and wealthy philanthropist George Soros - wants to turn Hungary into an "immigrant country", threatening its security and Christian identity.
Although Orban's actions, including refusing to participate in the EU's refugee resettlement scheme, have sometimes annoyed other European governments, Fidesz is afforded a measure of protection by virtue of its membership of the main centre-right EPP grouping in the European Parliament. "The EU is in Berlin, in Budapest, in Prague and in Bucharest". "The European Union does not mean Brussels, it means the European capitals together".