Ukraine's President Petro Poroshenko has flown out to Istanbul where the head of the Orthodox Church of Ukraine will be handed the tomos of autocephaly on January 6.

"For me it is a great honor, together with the newly elected head of the Orthodox Church of Ukraine, Metropolitan Epiphanius (Epifaniy) of Kyiv and All Ukraine, to depart for Istanbul where the long-awaited event will take place tomorrow," Poroshenko wrote on his Facebook page on Saturday.

He noted that he was heading to Patriarch Bartholomew "with the words of sincere gratitude on behalf of all Ukrainian people for the historical decision to grant the tomos to the autocephalous Orthodox Church of Ukraine."

The upcoming event will usher in "a new era in the history of global [Christian] orthodoxy," he said.

"We are praying for peace and unity. Because in unity is our people's strength. Unity is what will secure our victory," Poroshenko said.