Greek Socialist leader Evangelos Venizelos warned voters they were opening the gates of parliament to the «goose-stepping» far right and appealed for understanding over his party's support for austerity in return for an international bailout.

Venizelos took leadership of the Socialist PASOK party, for decades Greece's largest, earlier this year to try to win back support in next Sunday's election, when voters are set to punish those parties that backed painful austerity measures.

In an interview, the former finance minister warned against the rise of the ultra-nationalist party Golden Dawn, which could win around 5 percent of the vote, comfortably above the 3 percent threshold for entering parliament.

"Golden Dawn is an extreme phenomenon, I believe they are an example of fascism and we radically oppose them. It's an offense to our history and to parliament,» he told Reuters, suggesting Greece could be experiencing its version of Germany's «Weimar» years which led to the rise of the Nazi Party and Adolf Hitler.

Golden Dawn, which vows to expel both legal and illegal immigrants and meets under a flag of an ancient Greek symbol similar to the swastika, has won over many of Greece's poor by giving away clothes and food parcels.

It says it is simply a nationalist party and has attracted a large protest vote by attacking the bailout and what it calls German domination of Europe.

So concerned are the co-ruling parties about the rise of the far right that the government has in recent weeks rounded up thousands of illegal immigrants in central Athens and begun to build detention camps to house them in.

Venizelos suggested the only way for Greece to secure its future was to have several pro-European parties ruling in a coalition. «Over 75 percent of our people say they are for Europe and the euro. This must be expressed,» he said.

The powerful orator urged the European Union to address the rise of the far right in the region, suggesting the success of National Front leader Marine Le Pen in the first round of France's presidential election was proof of the lurch right.

She won about a fifth of the vote.

PASOK and its main conservative opponent, New Democracy, have seen support leak to smaller groups before the March 6 election, threatening their ability to form a government that will stick to the conditions of the international bailout to keep Athens from bankruptcy and in the euro zone monetary bloc.

The latest opinion polls showed New Democracy leading and PASOK in second. None of the four parties that follow support the bailout from the EU and International Monetary Fund.

Many of the fiscal cuts fell on important parts of PASOK's political base - public-sector workers - and the party has seen a mass of long-time supporters defect to other parties.

Venizelos has deflected some anger despite presiding over much of the program as finance minister. He was seen by many as a late comer to Greece's debt crisis, drafted in at the last minute by his predecessor Prime Minister George Papandreou, who has shouldered most of the criticism.

"We will not allow neo-Nazis to goose-step into parliament with Hitler salutes. Greek society will persevere, it will not submit to fascism,» Venizelos told 2,000 supporters on Friday evening in the western port city of Patras, reminding them how Greece had suffered under Nazi occupation in World War Two.

But the rally in a small indoor gymnasium was a pale imitation of the mass gatherings of earlier elections in Patras, a traditional socialist stronghold and seat of the Papandreou family which founded the party.

Locals remember when more than 100,000 people or half the city's population turned out to hear the late founder, Andreas Papandreou. In 2009, 53 percent voted for PASOK and 29 percent for New Democracy, electing four socialists to parliament.

"We should get two this time,» said long-time supporter Michalis Kanistras, 61, admitting George Papandreou's handling of the debt crisis that shook the euro and plunged Greece into its worst recession in decades, had eroded support.

"But Venizelos is giving new wind to the party. He knows how to handle the crisis, he has the brains,» he said.

Venizelos has revived the fortunes of PASOK since taking over from Papandreou in March, bringing the party from as low as fifth to second place.

Papandreou's last-ditch appointment of Venizelos, put his finance minister in the firing line. EU leaders criticized Venizelos for failing to abide by reforms, but he clinched a second, 130 billion euro ($172.37 billion) bailout and a debt swap that shaved over 100 billion euros from Greece's debt.

He faces the tough task of defending his party after decades of mismanagement and against a background of economic decline. With Greece in its fifth year of recession and one in five out of a job, many youths are leaving and the old barely make do.

"We are fighting hard to convince the Greek people that the path we follow is difficult but safe,» he said. «I am honest and self-critical but I try to explain that what we did was to protect, not hurt, the Greek people."

In the coffee shops of Patras people say they are disappointed in the party they have backed for years for not dealing with the city's problems. Dozens of illegal immigrants live in squalor near its port, hoping to sneak onto a boat out.

"At night, you can't walk around there. Papandreou disappointed us, especially because his family is from here,» said Giorgos Magdalinos, 37, an office clerk.

A gate to the west, the port city's old neoclassical buildings are dwarfed by modern apartment blocks. A state university boosts its economy and keeps its palm-lined promenade cafes bustling at all hours of the day.

Papandreou attended Venizelos's speech on Friday evening. They entered the gymnasium together to cheers from fans but also chants of «Thieves, Thieves!» from leftist protesters outside. Papandreou's aides said he would make no other appearances in Patras, where he is running as an MP.

"I backed PASOK in the last two elections but I don't even want to vote now. Many people say they will vote for Golden Dawn but I wouldn't. I might vote for one of the smaller, leftist parties,» Magdalinos said.

Venizelos said he was confident the European Union would agree with a plan to spread the pain of the austerity program over three years instead of two to give the economy a boost.

"Our difference with New Democracy is that we don't give old-party style promises,» he said. «We propose a complete plan to exit the crisis in three years instead of two. We have not yet agreed with (lenders) but I believe it will be accepted."

Political analysts say the two main parties will have no choice but to cooperate after the election, when they are expected to get a combined majority of roughly 35-40 percent.

But it will be a shotgun wedding.

New Democracy leader Antonis Samaras has made clear that, although he accepts the main goals of the austerity program, he will renegotiate how to reach them and that he would rather rule alone.

Venizelos said Greece needed a wider consensus and that he was confident people would vote for parties that would pull them out of crisis.

"The number of undecided is so large that discussing any result is pointless. The elections will be judged in the last three days,» he said. «Greek people may be bitter but are wise.» [Reuters]