"We will tell the president that if he considers his administration and National Security and Defense Council - where [ex-premier Viktor] Yanukovych's shadow government members are continually being admitted - to be his government, he should openly tell the Ukrainian people that he does not trust the cabinet, and dismiss it, to be able to work with Yanukovych," said Mykola Tomenko, a senior member of the bloc's parliamentary faction.
On Tuesday, the president appointed Konstantin Hryshchenko, an adviser to Yanukovych when premier, first deputy head of his administration. The National Security and Defense Council has been headed by Raisa Bohatyryova, a member of Yanukovych's Party of Regions, since December.
President Viktor Yushchenko and his aides have criticized Tymoshenko's government for failure to tackle economic problems, including soaring inflation. In March, consumer prices were up 26% from a year earlier, amid the global food price surge, and as the government repaid some of the population's savings lost when the Soviet Union collapsed.
In the latest blow to Tymoshenko's government, which was formed in December, Yushchenko cancelled its privatization plan, including the sale of the Odessa port's chemical plant and Turboatom nuclear equipment producer, saying the sale of strategic enterprises ran counter to law.
Yushchenko also said the government-proposed land plot auctions nurture corruption, while the deputy head of his administration, Ihor Pukshin, openly accused the ruling bloc of corruption.
Also on Wednesday, the leader of the Tymoshenko bloc's faction in the Supreme Rada said Yushchenko has been continuously thwarting the government's initiatives.
"The head of state and his entourage have been thwarting all the government's efforts," Ivan Kyrylenko said, demanding that presidential decrees blocking the initiatives be cancelled.
Tymoshenko was Yushchenko's closest ally in the 2004 "orange revolution" protests that brought him to power. He dismissed her as premier about eight months later, but she regained the post late last year. Both Yushchenko and Tymoshenko are widely expected to run for president next year.
