By Inti Landauro and Emma Pinedo
MADRID (Reuters) -Spanish conservative leader Alberto Nunez Feijoo will face a parliamentary vote on Sept. 27 to try to become prime minister, leaving him just over a month to gather sufficient support while even his own party sees his chances as slim.
Lower house speaker Francina Armengol said on Wednesday the investiture debate will begin on Sept. 26 and culminate in a vote the following day.
Feijoo, whose People's Party (PP) received the most seats but failed to win a working majority in a national election last month, was nominated by King Felipe on Tuesday to try to form a government.
A candidate for premiership needs to secure an absolute majority in the 350-member assembly in a first vote, or a simple majority of more yeas than nays in a second vote held within two days of the first.
Far-right group Vox and two regional parties have said they will back Feijoo, giving him 172 lawmakers, but he still faces an uphill battle to convince an array of regionalist groupings to back him or abstain in a second vote to be able to form a government.
"Feijoo has a very slim chance because the PP is not willing to do whatever it takes to govern," senior party member Esteban Gonzalez Pons told Onda Cero radio.
Winning over regionalist parties and keeping Vox on board is a difficult balancing act for Feijoo, as the far-right group is a stalwart opponent of decentralising the state and giving more autonomy to the regions.
The PP itself has been at odds for years with Catalonia's separatist parties. The Basque Nationalist Party (PNV) has earlier refused to negotiate with Feijoo due to his reliance on Vox.
Acting Prime Minister Pedro Sanchez says he will seek another term in office if Feijoo fails in his attempt.
Last week he was able to garner 178 votes to get his candidate Armengol elected as speaker, with support from his far-left partner Sumar and a tapestry of smaller parties including the PNV, Catalonian separatist Esquerra Republicana (ERC) and Together for Catalonia (Junts).
"Sanchez is willing to sell Spain in pieces to buy an investiture," Gonzalez Pons added, referring to the concessions he thinks Sanchez would make to get the support he needs.
If no candidate gets elected within two months after a first vote fails, a new election would take place after the Christmas holidays.
(Reporting by Inti Landauro and Emma Pinedo; editing by John Stonestreet, Andrei Khalip, William Maclean)