Thousands of people have turned out in Athens to warn the new crisis coalition that they cannot take any more austerity.
It comes the day after the government won a confidence vote in parliament. It can take some encouragement from opinions polls suggesting that three quarters of Greeks back the new prime minister – a non-party technocrat, breaking decades of either socialist or conservative rule.
Some demonstrations began early. Thursday is an important anniversary for the country that traditionally draws large crowds. Some 7,000 police officers are being deployed in Athens amid fears of violence.
The Finance Minister Evangelos Venizelos is overseeing talks with private sector bondholders to seek ways of cutting the Greek debt.
On Friday, the government will submit to parliament a budget of tax rises and spending cuts, to meet the demands of international lenders and secure the next slice of bailout funds.