The leader of Greece's conservatives, reluctant partners in a unity government, signalled on Thursday his main focus was on winning an election expected in February and reversing policies prescribed under an emergency bailout.

Antonis Samaras has infuriated Greece's EU peers over the past two years by refusing to back austerity measures aimed at averting national bankruptcy, and he said he would not cooperate with other parties after the election, slated for February 19.

His statements are further evidence of the rough road ahead of technocrat Prime Minister Lucas Papademos, a former vice president at the European Central Bank whose three-party coalition won a vote of confidence in parliament on Wednesday.

An opinion poll published on Thursday showed Samaras's New Democracy party had widened its lead over the Socialists of ex-prime minister George Papandreou, with its support rising to 32 percent from 30 in September.

Thousands of Greeks are due to protest on Thursday against painful spending cuts and tax hikes that have pushed their country into a fourth year of recession.

The size and mood of the rally, the first big protest in almost a month, will show the level of bitterness towards further austerity measures sought by the European Union and International Monetary Fund in return for more loans.

Many people don't expect any solution, but others hope too much. Deep inside, everyone knows policies cannot change and the measures may be even worse, said Mary Bossis, professor of International Security at the University of Piraeus.

Backed by New Democracy, its bitter rivals the Socialists and the far-right LAOS party, the cabinet must start meeting the terms of a new 130 billion euro bailout agreed last month.

Before that it must sign a pledge to assure the EU and IMF that it will do what it takes to make the deal work. In exchange it will get an 8 billion euro loan tranche it needs to avoid bankruptcy next month.

But any progress under its temporary mandate could be short- lived. We are working towards an absolute majority to implement our programme without delay and procrastination, Samaras said in an interview in the magazine Epikera.

When we can, we will change all that needs to be changed. But to do that, we will need a strong mandate in the coming election.

Polls show three quarters of Greeks back Papademos, a non-party technocrat, after decades of rotating rule by the PASOK Socialists and New Democracy. These two are blamed for piling up vast debts and leading Greece to the brink of default.

BUDGET

In Thursday's opinion poll, PASOK fell to 18.5 percent from 24.5, reflecting anger over Papandreou's shock decision last week to call a referendum over austerity measures he had already agreed with euro zone leaders.

That move raised doubts about Greece's future in the euro, led to Papandreou's resignation and, after four days of wrangling, Papademos's appointment.

Although the opinion poll showed no party would emerge from the election with a majority, Samaras said the experience of building the interim coalition had put him off cooperation with other parties.

We went through such labours for a three-month transitional government. Imagine if we had to agree on a government with a longer term, Samaras said. That's why I'm telling you an absolute majority is the only solution.

Apart from suggesting he would move to a pro-growth strategy, Samaras repeated that he would not sign the pledge demanded by Brussels swearing to do what it takes to see through the 130 billion bailout. He says his word is enough.

He added that he would insist on the February 19 polling date. Papademos and other officials have said the coalition government could last longer if needed.

Its first major task will be on Friday when it submits to parliament a 2012 budget of tax rises and spending cuts.

The Greek Finance Ministry said on Thursday it had begun talks with private sector bondholders represented by the Institute of International Finance on a bond swap which aims to cut around 100 billion euros from its debt.

Our goal is to structure a transaction that will attract the broadest possible support from the bondholder community, said Evangelos Venizelos, the minister of finance.

PROTEST

Thursday's rally commemorates Greece's 1973 student uprising that helped topple its military junta. After four years of recession, tax rises and cuts to pensions and wages, Greeks are fed up.

This government will do better (than the last) as long as it is just: crack down on tax evasion and target the rich. But I'm afraid they will cut my pension instead, said 70-year-old Dionysis Samaros who uses his 720-euro monthly payment to support himself and his family. How will we make ends meet?

November 17 marches have often been marred by violence between hooded protesters and police, who will flood the streets with 7,000 officers.

The afternoon march will wend its way past shuttered stores in central Athens to the embassy of the United States, which protesters blame for supporting the six-year dictatorship.

Unions have organised a series of protests in the two years since Greece requested its first international bailout. The last attracted more than 100,000 people and sparked fights between protesters that injured at least 70.

Ilias Iliopoulos, general secretary of public sector union ADEDY, said the rally was a first step in a tough battle.

Even if they don't take new measures, putting in place the latest austerity will bring Greeks to their knees, he said.

(Writing by Ben Harding and Michael Winfrey, Editing by Gareth Jones and)