BUENOS AIRES Defeated Argentine presidential candidate Patricia Bullrich signaled on Wednesday she will support far-right libertarian Javier Milei in next month's polarized runoff against Peronist Economy Minister Sergio Massa.

"The urgency of the moment forces us not to be neutral," conservative Bullrich told a press conference. "Argentina cannot start a new Kirchnerist cycle headed by Sergio Massa".

Bullrich amassed 23.8% of the vote in Sunday's first round election, finishing third behind surprise frontrunner Massa on 36.7% and Milei on just over 30% - a result that defied pre-election polls that had predicted a libertarian win.

"For Argentina to move forward it needs a root change," Bullrich said. "We have our differences with Javier Milei, that is why we competed. We don't hide them ... but we believe that we must join forces for a greater goal."

Some of Milei's proposals include dollarizing the economy and shutting the central bank.

Despite Bullrich's support for Milei, her broader conservative bloc "Juntos por el Cambio" remains split ahead of the Nov. 19 second round runoff as it comprises different cliques.

(Reporting by Nicolas Misculin; Editing by Steven Grattan)