"I have appealed the unconstitutional form and content of the law on the Cabinet of Ministers to the Constitutional Court," Viktor Yushchenko said.
The law allowing the parliamentary majority to nominate the prime minister and Cabinet ministers came into force February 2 after being published in a parliamentary and government bulletins.
The parliamentary speaker, Oleksandr Moroz, signed the law. Under Ukrainian law, the parliamentary speaker can sign a bill, approved by two-thirds of the votes in parliament, into law if the president fails to do so within a month.
Yushchenko first vetoed the bill January 12, but the Supreme Rada overrode the veto with 366 votes when a former opposition bloc joined the parliamentary majority that supports the largely pro-Russian Prime Minister Viktor Yanukovych.
Parliament also rejected all presidential amendments to the bill.
On January 18, Yushchenko again refused to sign the law, saying the Supreme Rada had made new changes to the document. The president described the law as giving the government " a false passport."
Yushchenko repeatedly said the provisions allowing factions to nominate the prime minister, defense and foreign ministers, as well as dismiss ministers, ran counter to the national unity pact political leaders signed in August in a bid to end the protracted political crisis in the ex-Soviet state.
Those appointments were the president's prerogative in the power-sharing deal between Western-leaning and more pro-Russian political forces.
Yushchenko also insisted that parliament should coordinate candidacies for deputy foreign and defense ministers with the president, and said that a provision allowing the Cabinet to cancel decisions made by local administrations should be abolished.
The development is the latest twist in the power struggle between the president and Yanukovych, whom Yushchenko defeated two years ago in presidential polls but was forced to appoint as premier last August, and will further consolidate the premier's power.