"Unless there is an alliance, it is impossible to oust BJP during the next state Legislative Assembly elections," Goa Forward (GF) president Prabhakar Timblo said.
"The people of Goa want a stable government post 2017 polls, and if non-BJP parties cannot assure the stability, the votes will be polled for BJP bringing it to power," he said.
Timblo said in the absence of an alliance, the votes of other parties will get divided.
The Congress recently ruled out any alliance during the polls and instead had appealed Sardesai to join the party.
Meanwhile, GF has said the response to Aam Aadmi Party's public meeting in Panaji addressed by its National Convener Arvind Kejriwal indicates that people in Goa are looking for an alternative to the Congress and BJP.
"The response which was received by AAP meeting is an indication that people of Goa are looking for non-Congress, non-BJP option for the Goa Assembly elections," Timblo said.