Angel Merkel, the German chancellor, has arrived in Greece in a bid to show support to the nation's embattled government as the public plan new demonstrations against austerity cuts.
Tuesday's visit to Athens is Merkel's first since the eurozone crisis erupted nearly three years ago.
The chancellor is considered by many Greeks to be the key architect behind the country's austerity measures.
Merkel has been criticised at home for avoiding a visit to the Greek capital to address the debt crisis, unlike EU President Herman Van Rompuy, European Commission President Jose Manuel Barroso and Jean-Claude Juncker, the eurozone chief.
Amid fears for Merkel's safety, authorities in the city have created safety zones to keep protestors away from proceedings as the chancellor conducts meetings with conservative Prime Minister Antonis Samaras and President Carolos Papoulias.
Leftist and Communist-affiliated unions are due to hold separate protests against austerity cuts and a three-hour strike has been called in Athens from midday onwards.
Local police have declared a ban on "public gatherings and demonstrations" in a broad section of the city centre which includes the German embassy, parliament and the offices of government.
But the union gatherings are expected to lie outside this area and will go ahead as planned.
Al Jazeera’s Barnaby Phillips, reporting from Athens, said: "Angela Merkel has decided that this government is her last chance to have co-operation from Greece after all the economic and political turmoil there has been in this country over the past two years.
"The alternatives if it were to collapse are very frightening from her point of view. So it’s symbolic, she's showing that she supports it.
"But she is always walking that tight line between the anger on the Greek streets, and the concerns of her own electorate back in Germany, that Greece, quite frankly, is a bottomless pit into which the German voter feels he or she has already put far too much money," he added.
When Samaras visited Berlin in August, Merkel had insisted that she wanted the debt-ridden country to stay in the euro and pledged German help after crisis talks with the Greek prime minister.
On Monday, Merkel's spokesperson Steffen Seibert told a news conference that she would convey a message of support for "ambitious" cuts already in place in Athens and encouragement to stay the course.
Seibert said: "She is going to Greece to express her support for the ambitious reform efforts that the Greeks have set out and are, in part, beginning to implement.
"We should not forget, and I think this is sometimes forgotten in Germany, that Greece can point to some successes when it comes to reducing the deficit through very difficult measures."