By Inmaculada Sanz and Sarah White
MADRID (Reuters) - The leader of Spain's second-largest opposition party, Podemos, ruled out acting as a junior partner in an alliance with other left-wing forces, potentially improving conservative Prime Minister Mariano Rajoy's chances of serving a full term.
Opposition groups outnumber Rajoy's center-right People's Party (PP) in the Spanish parliament, but divisions among the two main left-leaning blocs have hindered their attempts to forge a front against him since a 2016 general election.
Pablo Iglesias, who led anti-austerity Podemos ("We Can") into third place last year with about a fifth of the vote, said in an interview that his party did not see itself ceding the lead role in a Portuguese-style alliance to the center-left Socialists, which came second with only a slightly higher score.
"We're almost on a par with the Socialist party, we even scored more than them in some areas, so I don't think it would be sensible for anyone to offer a relationship as a junior partner to someone who is an equal," Iglesias said.
In neighboring Portugal, the center-left Socialists have been at helm of a minority government since 2015 with the backing of two smaller far-left parties, in an alliance which has proved more stable that analysts and rivals had projected.
Pedro Sanchez, the newly re-elected head of the Spanish Socialists, has often praised the Portuguese formula, a rare success story for the European center-left which is increasingly struggling. [nL8N1HA06L]
Sanchez's comeback after he was ousted as the Socialist leader last year has raised expectations that Rajoy would face a rougher ride in parliament than he has since being re-instated for a second term last October with a minority mandate.
But the Socialists and far-left Podemos, a young party which was born out of street protests during a recent recession, are vying to occupy the same space in Spanish politics and have rarely been on the same page in terms of opposing Rajoy.
Next week, for instance, the Socialists are set to abstain in a motion of no confidence against Rajoy filed by Podemos, criticizing the motion for being too hastily put together without a prior consensus.
Iglesias did not rule out voting in favor of a motion of no confidence that would be put forward by the Socialists instead but such a move remains highly hypothetical given both leaders have repeatedly failed to agree on forming a government in the wake of Spain's elections in 2015 and 2016.
(Editing by Julien Toyer)