Portuguese Prime Minister Pedro Passos Coelho. (AFP Photo)
Portugal's Socialist opposition leader said Wednesday it would take a "Martian invasion" to convince him to join a coalition government, after the ruling centre-right bloc fell short of outright election victory.
Pedro Passos Coelho's "Portugal Ahead" coalition notched up 38.6 per cent of the vote in Sunday's ballot, short of an absolute majority, leaving him needing support from other parties to govern.
President Anibal Cavaco Silva on Tuesday tasked Passos Coelho with forming a "stable and lasting government", but in a stark indication of the challenges facing the 51-year-old, Socialist leader Antonio Costa scoffed at the idea of a deal.
A coalition with the centre-right "is only imaginable in an extreme situation, like a Martian invasion", Costa said on Wednesday.
President Silva had called for compromise -- he has never concealed his support for a "grand coalition" uniting left and right.
Passos Coelho's victory at the polls came despite overseeing four years of painful austerity measures imposed so the debt-hit country could receive an international bailout.
The anti-austerity Socialists placed second with 32.4 percent of the vote, retaining its status as the main opposition group in parliament.
After a meeting of his party, which looks increasingly divided after its electoral defeat, former Lisbon mayor Costa said he would begin consultations with "all political forces".
On election night he had hinted at compromise, saying he would fight to "end the chapter of austerity," but would not threaten Portugal's commitments towards its creditors.
The country emerged in May 2014 from a three-year, 78-billion-euro ($88-billion) bailout from the European Union and the International Monetary Fund.
Stability Pledge"We will do everything we can to stop the election becoming the precursor to political instability," said Passos Coelho, who is expected to meet the Socialist leader on Friday.
Passos Coelho's Social Democrats on Wednesday signed a new coalition deal with their conservative Popular Party partners.
The centre-right alliance holds 104 out of the seats decided so far, against 85 for the Socialists, and is certain to fall short of the 116 needed for outright control of the 230-seat legislature.
Four seats to be decided by votes from Portuguese expatriates will be determined by October 14.
That means that Passos Coelho will have to get the support, or at least the acquiescence, of other groups. The house is dominated by leftist parties, which hold 121 seats and could threaten a minority government.
Costa has let it be known that he was not ready in the short term to join forces with the Communist Party or the Left Bloc to stymie the right -- but he did not completely rule out future accords.
Portugal must present the key aspects of its 2016 budget to the European Commission by October 15 -- a key test for any future agreement between the centre-right and the Socialists.
On the campaign trail Costa threatened to block any centre-right government's budget, but on election night he showed a more conciliatory side and analyst Antonio Costa Pinto said he has little room for manoeuvre now.
Weakened by the poll defeat, "the Socialists will end up supporting government policy to give themselves time to sort out their internal problems," Pinto said.
And the Socialists will be wary of forcing early elections in case voters punish them at the ballot box for precipitating a political crisis.
Moreover, under the Portuguese constitution, a newly elected parliament cannot be dissolved before six months, so no election could be held before April 2016.
Since the arrival of democracy in 1974, Portugal has seen several minority governments, from both left and right, but only one managed to serve its full term.