The decision was announced by KPCC President V M Sudheeran after the party's high power committee meeting here today.
Three seats from Kerala will fall vacant in the Upper House as the terms of Congress leader Antony, CPI(M) leaders T N Seema and K N Balagopal are due to expire this month.
Of the three seats, ruling Congress led-UDF can win two and CPI(M)-led LDF opposition one, based on the strength of the legislators of both the fronts.
UDF has decided to allot the second winnable seat to its pa
LDF is yet to decide on the one seat they can win. CPI has demanded that they be given the seat.
Meanwhile, an official release said that election for the RS seats falling vacant would be held on March 21.
The last date for filing of nomination is March 11 and withdrawal on March 14.
Election and counting of votes would take place on March 21, the release added.