Yushchenko's criticisms followed Friday's enactment by parliament of a law substantially curtailing presidential powers.
The new legislation, which came into force despite having been vetoed by the president twice, allows the parliamentary majority to nominate a prime minister and Cabinet members, including defense and foreign ministers - appointments that have until now been a presidential prerogative.
Yushchenko argued the law runs counter to the national unity pact and said he would file an appeal with the Constitutional Court.
As he met with PM Viktor Yanukovych and Speaker Oleksander Moroz Monday, Yushchenko accused them and other coalition government leaders of "ostentatiously ignoring" the pact and other inter-party deals.
He said the primary aim of the agreements is to maintain stability in the country, and that all branches of the government should engage in a meaningful dialogue and work toward compromise.
Speaking to reporters following the meeting, Yanukovych said the president will retract his appeal against the controversial law if a compromise deal is reached with parliament.
"If these issues [law provisions laying down the procedure for appointing the prime minister and ministers of defense and foreign affairs] are considered in parliament and differences are overcome, the president will withdraw his appeal," he said.
Last week, parliament sacked Foreign Minister Borys Tarasyuk, a key Yushchenko ally who had actively promoted the president's pro-Western policies, including his bid to take Ukraine into NATO and the European Union.
In a separate development Monday, Yulia Tymoshenko, Yushchenko's main ally in the 2004 "orange" revolution and now the leader of an eponymous opposition bloc, threatened to obstruct the Supreme Rada's work until lawmakers pass legislation on public utility prices and the transportation of natural gas.
"We will not let [the Supreme Rada] work until the gas transportation bill is voted in, as well the one concerning the prices of housing and utility services," she said.
Tymoshenko said ways to protect Ukraine's population against utility price hikes and to prevent foreign interference in the country's gas transportation system will be high on the agenda of her talks with the president later in the day. The meeting is set for 5 p.m. local time (3 p.m. GMT).
Last Friday, Tymoshenko said her bloc would support a motion to sack Moroz, which the pro-presidential Our Ukraine faction put forward after the parliamentary speaker signed into law the bill on Cabinet appointments.
Moroz, the leader of the Socialist Party, was placed at the helm of the Supreme Rada in August after he abandoned a Tymoshenko-led alliance of "orange" forces in favor of Yanukovych's pro-Russian coalition.
