"Today I signed an appeal to parliament demanding that it rescind the unconstitutional decision to fire the current government," Mr Yushchenko said as he opened an extraordinary cabinet meeting two days after parliament's vote.
The Ukrainian president charged that Tuesday's vote was illegitimate and was taken "in order to form an unstable situation in Ukraine" by a parliament that is a holdover from the Russia-backed regime ousted during the "orange revolution" protests in late 2004.
The current parliament was elected in 2002, and Mr Yushchenko's administration has made clear that it regards the legislature as an outdated, unrepresentative throwback to an era when a regime backed none too subtly by Russia ran the country.
The standoff between Mr Yushchenko and parliament comes ahead of a March 26 parliamentary election, which will decide the fate of the pro-Western course that the president has set for ex-Soviet Ukraine.
Resolution uncertain
How the conflict will be resolved is uncertain as the body that would ordinarily mediate it, the constitutional court, is unable to convene because the legislature has balked at scheduling a swearing-in session for a number of new judges.
The dispute is being nervously watched in Brussels and Washington, which supported Mr Yushchenko during the "orange" protests and have urged all sides to respect the law in the dispute and to ensure stability during the election campaign.
Mr Yushchenko also said Thursday that he was withdrawing his signature from a controversial September memorandum of understanding with his "orange revolution" nemesis, Viktor Yanukovich, saying that the former premier's party had "violated fundamental principles" of the agreement by supporting Tuesday's vote.
Parliamentarians who voted to dismiss the government on Tuesday said they did so because of a deal that the cabinet struck with Russia in early January to end a bitter standoff over gas supplies, which saw prices for Ukraine nearly double.
But most pundits and politicians in Ukraine say that the Russian deal served as a pretext for the opposition to strike a blow against Mr Yushchenko and his allies ahead of the election.
The ratings of Mr Yushchenko and his supporters have plummeted during the past year against the background of a sharp economic downturn, heightened tensions with Russia and general political turmoil.
Behind in polls
His Our Ukraine bloc currently trails Mr Yanukovich's party by 10 to 15 percentage points in opinion polls.
The March poll promises to be a bitter campaign, as it is the first one after constitutional changes entered into force on January 1 transferring important powers from the president to parliament, including the right to name the prime minister and form a government.
Mr Yushchenko needs his allies to score decisively in the vote in order to continue driving Ukraine toward membership of the European Union and the North Atlantic Treaty Organization (NATO).
Tuesday's cabinet dismissal was the second in four months and followed Mr Yushchenko's sacking of the government of his "orange revolution" partner Yulia Tymoshenko in September.