The Yulia Tymoshenko Bloc filed two suits and Our Ukraine one protesting the breakup of the "orange" coalition, the emergence of the "anti-crisis" coalition and the election as parliamentary speaker of Oleksandr Moroz, leader of the Socialist Party and their former ally.
"The lawsuits have arrived, have been registered and are being prepared for examination," the court in question said Wednesday.
Moroz said Tuesday Ukraine had formed a new parliamentary coalition - the second one since the March 26 elections - comprising the pro-Russian Party of Regions, the Communist Party and the Socialist Party.
The "orange" coalition of Tymoshenko's eponymous bloc, pro-presidential group Our Ukraine and the Socialist Party - so named because they were the driving force of the 2004 "orange revolution" that propelled Viktor Yushchenko to the presidency - fell apart when the Socialists did a deal with the opposition that saw Moroz installed as speaker.
Also on Tuesday, the Party of Regions, the largest faction in the Supreme Rada and the core of the coalition, nominated its leader Viktor Yanukovych, who was prime minister in 2002-2004, for the job again.
Tymoshenko, who was widely expected to return to the prime minister's chair she occupied for eight months last year, said Tuesday her faction would go into radical opposition and was ready for new elections.
The 450-seat legislature descended into chaos, as members started numerous fist fights, traded insults and attempted to drown each other out with sirens and megaphones Tuesday.
The situation seems to have deteriorated further Wednesday with thousands of people gathered in front of Ukraine's parliament to protest the political turmoil and support their political parties.
Moroz said Wednesday the court had been subjected to pressure to force it to accept the suits and announce the Rada's activities since July 7, when the new coalition was formed, illegitimate.
President Viktor Yushchenko can dissolve the Rada as the deadline for the formation of a new government expires July 24.
