BUDAPEST, March 11 (Reuters) - The main Hungarian opposition party Tisza's lead over long-time Prime Minister Viktor Orban's Fidesz shrank slightly in a poll published on Wednesday, as campaigning enters its final month before an April 12 election.
Nationalist Orban faces the biggest challenge to his rule in 16 years, although the outcome of the vote - coming against the backdrop of the Ukraine-Russia war and building economic challenges - remains highly uncertain, with opinion polls showing that many voters are still undecided.
A poll by 21 Research Centre (21 Kutatokozpont), conducted between March 2 and 6 and released on Wednesday, showed Tisza leads by 14 percentage points ahead of Fidesz among decided voters, down from a 16-point lead in the agency's last poll in January.
Centre-right Tisza, led by former government insider Peter Magyar, had the support of 53% of decided voters, unchanged from January, according to 21 Research Centre, while 39% backed Fidesz, up from 37% in the previous poll.
The poll, published by news site 24.hu, showed 38% support for Tisza among all voters, with Fidesz backed by 30%.
Based on the poll, Tisza could win 115 seats in Hungary's 199-seat parliament, and Fidesz could expect 78 seats. The far-right Our Homeland (Mi Hazank) party would be the only other party crossing the 5% threshold to win seats.
Magyar has said his party would curb corruption, unlock billions of euros in frozen European Union funds to boost the economy, and firmly anchor Hungary in the EU and NATO.
Fidesz has pointed to other surveys that still show it on course to victory, though opponents - who criticise Orban for harming the rule of law and keeping warm ties with Russia - say these have mainly been conducted by institutes with financial or personal ties to the ruling party.
(Reporting by Anita Komuves; Editing by Alex Richardson)
