Batkivschyna opposition faction leader Arseniy Yatseniuk has confirmed his rejection of the post of prime minister.

"You have heard that Viktor Yanukovych offered me the post of prime minister. My answer to Yanukovych is such: you cannot buy me with posts, Mr. President. Go buy your associates," Yatseniuk said at a people's assembly on Kyiv Independence Square on Sunday.

He said the opposition was forming its own government and it was a unanimous decision of all opposition leaders and former Prime Minister Yulia Tymoshenko.

The opposition will not negotiate a constitutional reform at the office of Verkhovna Rada Speaker Volodymyr Rybak; it demands that the reform be put to a vote on Tuesday, Yatseniuk said.

"Our struggle is not a debate. I want to be honest and frank with you. Do I believe the negotiations will bring results? I practically do not. We have heard enough words, we need deeds. That is why, there will be no secret negotiations at the office of the parliament speaker. We will bring [the issue] to the [parliament] hall and have a roll vote: who is for Ukraine and who is against it," Yatseniuk said.

The Ukrainian parliament is also due to vote on a resolution reinstating the 2004 constitution on Tuesday, he said.