Details around the South Stream gas pipeline project and the fifth no-confidence motion tabled against the government are to top the agenda at Friday's session in Parliament.

Prime Minister Plamen Oresharski and Economy Minister Dragomir Stoynev have confirmed they will appear before lawmakers for a hearing on South Stream upon request by the opposition. The ruling socialists have however also backed the move.

Oresharski surprisingly declared on Sunday that Bulgaria was freezing the South Stream project to comply with EU requirements, days after the EU Commission launched an infringement procedure against Bulgaria over irregularities with the project and demanded that it provisionally come to a halt.

On Wednesday he announced he would reveal "the truth" about South Stream during the parliamentary hearing.

His decision, which sparked controversy among cabinet members, drew resistance from Parliament Speaker Mihail Mikov, who explained Thursday the project was still under way and Oresharski was not capable of unilaterally taking such a step.

It is unclear whether the session will actually be held; Thursday's debates on a referendum proposal regarding the voting system failed after lawmakers from opposition GERB, which had for months spoken in favour of the referendum, did not registered and no quorum was reached.

Parliament Speaker Mikov later said that the referendum could also be discussed on Friday.

Center-right opposition GERB have voiced their resolution to submit consecutive motions of no confidence that could finally bring the term of the ruling socialist-liberal coalition to an end.

The latest vote is on fiscal policies, with GERB lawmakers accusing the Bulgarian Socialist Party (BSP) of putting the financial system in jeopardy by opting for risky billions-worth loans.