Ukrainian heavyweight boxer and opposition politician Vitali Klitschko said on Thursday he would run for president in 2015 and angrily rejected legislation that could disqualify his candidacy because of years he spent training in Germany.

Klitschko, 42, the reigning WBC heavyweight champion, made his declaration to parliament after its deputies - predominantly from the ruling Party of Regions and its allies - amended a law on tax legislation in a way that could be used to prevent him from running for the presidency.

He is the first declared contender against incumbent Viktor Yanukovich, who is widely expected to seek a second term despite a slump in popularity because of Ukraine's faltering economy.