As opinion polls show Syriza ("Coalition of the Radical Left") widening its lead ahead of Sunday's parliamentary election, the head of Greece's Socialist PASOK party told Reuters on Wednesday that his party could support a government led by the leftists. Evangelos Venizelos said the only proviso was that Syriza form a wider pro-euro alliance.

"Syriza alone, or allying only with Syriza is not enough," Venizelos said in the interview.

Venizelos, current deputy prime minister in the outgoing coalition led by the center-right New Democracy party, said PASOK wanted a broader representation of opinion in the new government.

PASOK rocketed to power in 2009 with 44 percent of the vote, but after revealing Greece's perilous financial circumstances in 2010 and implanting harsh austerity policies required by the EU and the IMF for the ensuing emergency loans, voters began to desert the Socialists in droves. Polls showed PASOK holding 3 to 5 percent voter support ahead of Sunday's election.

Throughout the campaign, Syriza has resisted talk of an alliance with any party besides the Communists, though it has promised to seek wider consensus should it emerge as the dominant party.

The danger of making 'easy promises'

Analysts think PASOK would provide a much-needed moderating influence on Syriza, which has upset financial markets and fellow eurozone governments with its campaign promises to renegotiate the terms of Greece's bailout and revoke some of the painful austerity measures put in place as a result.

European shares took another dive after a four-day rally as Syriza solidified its lead.

Venizelos, who served as finance minister at the peak of the crisis, urged the radical leftists to exercise caution in their financial policy, warning that "amateur proposals" posed a serious danger to the country. He added that voters might be shocked and disappointed by Syriza's ability to make good on "easy promises" once in office.

es/msh (AFP, Reuters)