Former Union of Democratic Forces leader Martin Dimitrov has issued a strong statement of disappointment with the deepening disunity of the two main heirs of the Blue Coalition the UDF was part of.

"Bulgaria's right has lost its good sense," wrote Dimitrov using his Facebook page.

He renewed his criticism of the May 2012 UDF decision to break up the Blue Coalition that led to his resignation.

"At present, support for the Union has shrunk to 0.5-0.5%," said Dimitrov, adding that his former party will face "catastrophe" at the May 12 early elections.

Dimitrov also alluded to the rift between the other senior partner in the Blue Coalition - Democrats for Strong Bulgaria - and the Unity movement, newly founded by UDF dissenters.

Democrats for Strong Bulgaria and Unity had filed a registration with Bulgaria's electoral body as a coalition, only to see Unity withdraw its registration hours later.

Dimitrov clarified he was not part of negotiations between the two entities.

"What is obvious is that there should have been a unification and a road towards a new common party to the benefit of Bulgaria's democrats," said the former leader.

"Instead, we are witnessing the latest in a long string of splittings, a long string of games that seem to be heading towards a sorry end," added he.

Dimitrov concludes by saying that the situation apparently leaves him with "no one to vote for" in May.