Bulgaria’s formerly ruling party GERB is to introduce a demand, signed by 77 of its MPs, for an immediate extraordinary parliament sitting over the presidential veto on the budget revision.

The center-right party believes a sitting should be held as soon as possible.It will table the signatures in Parliament on Friday.

“GERB introduces a demand for an immediate parliamentary sitting with only one item on the agenda – deliberations on the presidential veto on provisions of the recently adopted budget 2013 update” declared GERB's MPs.

Bulgarian Parliament Chair Mihail Mikov had scheduled an extraordinary parliament sitting over the veto for August 30.

Under local regulations the parliamentary speaker is obliged to convene parliament within seven days if one-fifth of the 240 MPs demand that.

In a Wednesday statement, Bulgaria's head of state Rosen Plevneliev announced he had imposed a partialveto on the Law on Amending and Supplementing the State Budget Act for 2013, saying the Socialist-led coalition government had not shown enough transparency in its use of public money.

He explained that the package of social measures included in the budget update constituted a very small share of the earmarked expenses.