The press service also said two other nominees - acting Prime Minister Yuriy Yekhanurov and the head of Our Ukraine's political committee, Roman Bezsmertny - had withdrawn their candidacies.
Our Ukraine's political council was scheduled to approve Poroshenko's candidacy at a session due 5.00 p.m. Moscow time (1.00 p.m. GMT).
Poroshenko, one of President Viktor Yushchenko's closest associates and Ukraine's richest men, owns a number of food industry enterprises and headed the Ukrainian National Security Council in February-August 2005.
Our Ukraine is one of three movements - the others being the Yulia Tymoshenko Bloc and the Socialist Party - that entered talks on forming a parliamentary coalition after a March 26 election failed to produce a clear winner, but disagreements over distribution of posts kept them from reaching an agreement.