Thousands protesters denounced austerity in peaceful rallies in central Athens on Tuesday, as part of the annual international May Day mobilizations for workers' rights, a few days before the crucial parliamentary elections to be held on May 6.

Young workers who have suffered some 25-40 percent salary cuts over the past two years amidst deep recession, joined the increasing numbers of jobless in demonstrations organized by the two umbrella labor unions of public and private sector employees ADEDY and GSEE along with leftist parties.

Marching from the City Hall to Syntagma square in front of the parliament during a nationwide general strike, they raised banners with slogans such as "No Pasaran (The will not pass)."

It was a reference to the painful austerity measures introduced since 2010 in return of multi-billion euro international aid packages to address the debt crisis that has threatened the eurozone member state with default.

"I chose to participate in the last such protest before the elections which are critical, since there is hope for a change in leadership, for an end to the bailout agreements with international lenders," private sector employee Evangelia Voyatzi told Xinhua.

Economy is the key issue in the upcoming elections and the increasing percentages in recent opinion polls of parties that oppose austerity and the agreements with EU counterparts and International Monetary Fund, have fuelled hope of a possible change of course amongst some Greeks.

The frontrunner conservatives of New Democracy and the socialists of PASOK that support the austerity and reform program and the outgoing transitional six-month coalition, are expected to struggle to secure jointly parliamentary majority.

Local political analysts have expressed anxiety whether the new administration to emerge from the ballots in upcoming Sunday will push through the policies agreed in exchange of further aid over the next two years and a sound future of the country within the eurozone.

Shortly before the polls, many Greek voters appear angry and disappointed over the record high unemployment rates, the dramatic decline in their income and the long- awaited return to growth, as Athens has missed initial targets. They strongly denounce the rounds of austerity cuts.

"There is no other way. These measures are killing the average Greek family. We should focus more on growth than cutbacks on wages, pensions and tax hikes. My generation struggled for workers' rights. We will continue to struggle," pensioner Nikos Layonikas told Xinhua at Syntagma square, before marching off chanting "No to austerity."

Tuesday's demonstrations in Athens ended with minor scuffles between youths who briefly clashed with ant-riot police, after damaging a few pre-election kiosks.

Similar rallies were staged across the country, as mass transport services were disrupted by work stoppages, hospitals run on skeleton stuff and public sector offices and stores remained closed.