"The politburo meeting is taking place after a majority of party's West Bengal unit favoured forming alliance with Congress for assembly polls there.
"The party's Kerala unit though has some concerns as Congress is our main rival in the southern state. Whatever decision the politburo takes will be placed during central committee meeting to take a final call in this regard," party sources said.
The two-day central committee meeting will begin tomorrow.
The sources added the ongoing JNU row was also discussed during the meeting.
The party has been at loggerheads with the Centre after the arrest of JNUSU president Kanhaiya Kumar on sedition charges.