Finland is headed for a close-fought parliament election on April 2, with the three largest parties in a near dead heat, an opinion poll published by daily Helsingin Sanomat showed on Tuesday.

Support for the right-wing opposition National Coalition Party declined by one percentage point from last week to 19.8%, narrowly ahead of the ruling Social Democrats and the nationalist Finns Party with support of 19.2% each.

The leader of the largest party in Finland normally becomes prime minister, provided he or she can put together a coalition.

The outcome of Sunday's vote will thus decide whether National Coalition leader Petteri Oropo or Finns Party leader Riikka Purra can replace Prime Minister Sanna Marin of the Social Democrats.

With as many as 10 parties currently represented in parliament, the ultimate formation of a government will likely be subject to post-election coalition talks lasting weeks.

The March 9-25 poll by Kantar Public has a margin of error of 2.1 percentage points. (Reporting by Essi Lehto, editing by Terje Solsvik)