The governing coalition of Bulgaria must prepare for a challenge to the recent introduction of compulsory voting from the Constitutional Court, Parliament Speaker Tsetska Tsacheva said on Tuesday.

At a meeting of Prime Minister Boyko Borisov with leaders of political parties that are in or back the cabinet, also attended by Tsacheva, she said it was "high time" for the top court to issue a definitive ruling, "since this drama with the referendums, questions, and [legislative] amendments should end once and for all", according to the meeting's transcript published on the Palriament's website.

Changes were agreed at the meeting to controversial sections of the Electoral Code that were amended last week, prompting public outcry.

Compulsory voting, which was also introduced, was a key target of civic groups, but has not yet been reversed by Parliament since the leaders' meeting.

Prime Minister Boyko Borisov said earlier this week he did not support compulsory voting at all, but was forced to accept it because of his agreement with the Patriotic Front, a nationalist coalition which has no ministers but backs the government.

At the Tuesday meeting, the Reformist Bloc, the junior coalition partner, said it would "not abstain" in the vote on the proposal, and neither would the biggest opposition parties, socialist BSP and liberal DPS.

Opponents of compulsory voting cite Bulgaria's Constitution, whose Article 10 reads that: "Elections and national and local referendums shall be held on the basis of universal, equal and direct suffrage by secret ballot."