Velizar Enchev, an MP who quit the nationalist coalition Patriotic Front (PF) last year, has announced he is due to set up his new organization on April 4-5.
The entity is due to be founded in the city of Veliko Tarnovo, the old capital of Bulgaria lying in the north-central part of the country.
Enchev told private national channel NOVA TV that the nascent political organization should compared to Greece's left-wing SYRIZA and will be largely modeled after it.
SYRIZA won by a landslide the parliamentary elections in Greece on January 25, and formed a coalition with the Independent Greeks party (ANEL) to try to end austerity. The Athens government has been involved in a bitter dispute with Europe and the International Monetary Fund (IMF) over the issue since the new cabinet was formed hours after the election.
In Enchev's words, its Bulgarian replica will be "a social movement with left-wing messages" and no leader-type model.
He added there will be collective decision-making, with "young figures" also involved, though he refused to give any names.
The former key Patriotic Front member left the parliamentary group of PF in December 2014, arguing the NFSB (National Front for the Salvation of Bulgaria), one of the two main parties in PF of which he was a member, is blindly following the orders of its leader Valeri Simeonov.
Enchev was later expelled from the NFSB.