Greek police and protesters have clashed in Athens as anger over government spending cuts in the debt-ridden nation continues to fester.

Officers fired tear gas after a group of several hundred demonstrators rallying against the austerity measures threw stones at riot police.

However police said the majority of the estimated 12,000 protesters marching on parliament in the capital were behaving peacefully.

Their action came after unions called impromptu strikes on Friday in protest at the $6.5bn package, which will see tax rises, public salaries frozen and the retirement age raised, in an effort to curb the nation’s debt crisis.

A number of high profile injuries in the protests sparked “mayhem” in the capital. A prominent union leader was seen being punched in the face, apparently by another member of the crowd. Then a man named Manolis Glezos who is very well-known in Greece and considered the ‘grand old man of the left’, was seen being carried away injured. High profile injuries have inflamed the crowds and led to 45 minutes of mayhem in the city center.

Consensus in Greece for the austerity measures appears to be fraying, making a difficult situation for George Papandreou, the Greek prime minister.

Papandreou is currently embarking on a diplomatic quest for concrete support from European leaders to ease his country’s debt crisis.

He has already ruffled Europe’s feathers by warning that Greece could request financial help from the International Monetary Fund unless the EU details potential emergency support.

Jean-Claude Juncker, head of the group of eurozone finance ministers, said after meeting the Greek prime minister in Luxembourg on Friday that “we have to deal with the problem as a euro area”.

He said it was acceptable for the IMF to offer technical assistance, but insisted that “as the chairman of the euro group I’d like to exclude any further involvement of the IMF”.

Papandreou, who is due to meet Angela Merkel, the German chancellor, later on Friday, has said Greece needs “support” from Europe “so that we can borrow money under reasonable conditions”.

Earlier, Rainer Bruederle, Germany’s economy minister, said Berlin had no intention of offering Greece “one cent” in aid.

Friday’s strike saw state schools closed, while hospitals functioned with emergency staff and all Athens public transport was idle.

George Papaconstantinou, the Greek finance minister, said the belt-tightening would work if unswervingly enforced.

“In emergencies, governments take emergency measures,” he told politicians during an austerity law debate.

“Will we succeed? Yes, we will. Will we have to take further measures? No, provided we implement the program we have submitted. And we will.”