The country is in a crisis with fighting in the Supreme Rada and protestors on the streets following the collapse of a Western-leaning parliamentary coalition and the emergence of a new "anti-crisis" coalition led by the Party of Regions.
Viktor Yanukovych said that if the president fails to nominate a candidate, "another procedure will come into force - three factions will put forward a proposal, and then parliament will vote."
Yanukovych, who was the main opponent of current President Viktor Yushchenko in the country's 2004 presidential race, and held the post of the prime minister under former President Leonid Kuchma in 2002-2004, said it was a direct presidential duty to nominate a prime minister.
The post of the premier is currently a stumbling block in the Supreme Rada with both Yanukovych and Yulia Tymoshenko, a 45-year-old leader of the eponymous block, competing for the post. Before the Western-leaning "orange coalition" collapsed, Tymoshenko was widely expected to return to the prime ministerial post she occupied for eight months last year.