TEHRAN, Young Journalists Club (YJC) - "We declare our withdrawal from the current coalition, the cessation of its activities ... and the initiative to form a new coalition with a new agenda," Maksym Burbak, the People's Front faction leader, told parliament.
Parliament now has one month to form a new coalition or else the president can dissolve parliament and call snap parliamentary elections.
Zelenskiy won a landslide against Poroshenko last month but his newly formed party lacks any representation in parliament.
A snap election would probably suit Zelenskiy, whose popularity is high and whose party is on course to win the election while falling short of a majority.
Zelenskiy, a comedian with no prior political experience, is due to be inaugurated on Monday.
Speaker Andriy Parubiy told parliament the coalition had ceased its activities and said "within one month from today ... a new coalition should be formed."