By Essi Lehto

HELSINKI (Reuters) - Finnish central bank Governor Olli Rehn said on Wednesday he plans to run for president next year when Finland is due to elect a new head of state, and will seek leave of absence from his current job.

The 61-year-old, who sits on the governing council of the European Central Bank, said he will be on annual leave in the time ahead and will not be engaged in official duties while preparing to run.

He must collect 20,000 signatures before he can formally enter the race.

"I will apply for a leave of absence when hopefully I am nominated as a presidential candidate," Rehn told a news conference.

Pekka Haavisto, who on Wednesday stepped down as Finnish foreign minister as the government resigned following general elections, recently announced that he was running for president.

Foreign and security policy are among the key constitutional responsibilities of Finnish presidents.

Finland in April joined the NATO military alliance in a historic policy shift brought on by Russia's invasion of Ukraine that drew a threat from Moscow of "counter-measures."

(Reporting by Essi Lehto, editing by Terje Solsvik)