EU Commission President Jose Manuel Barroso has told Greece's new government to "deliver, deliver, deliver" on promises for cost-cutting reforms.
The country depends on the reforms for continued financial support from other euro zone members.
"To maintain the trust of European and international partners the delays must end. Words are not enough. Actions are much more important," Barroso said at a joint news conference with conservative Greek Prime Minister Antonis Samaras after the two met.
Mr Barroso said he was assured by Samaras that the coalition government would respect the commitments under the second bailout programme and would speed up key structural reforms.
"Greece is part of the european family and the euro area and we intend to keep it that way," Mr Barroso said.
"All the heads of state and government of the euro area have stated in the clearest possible terms that Greece should stay in the euro as long as the commitments made are honoured," he added.
Mr Samaras said the Greek government would comply and "move ahead to implement structural changes, privatisations and implementation of the measures that have been agreed in order to reduce the deficit."
Meanwhile, the heads of an inspection team from the European Union, the International Monetary Fund and the European Central Bank also arrived in the Greek capital to inspect the country's shaky public finances and the future of its rescue loan programme.
Parties in the month-old Greek government have finalised proposals to slash €11.5 billion in government spending over two years.European Central Bank head Mario Draghi is raising expectations the central bank might step in and help lower the high borrowing costs.
These borrowing costs are putting pressure on government finances in Europe.
Mr Draghi said in London that the bank would "do whatever it takes to preserve the euro" and added, "believe me, it will be enough."
Possible Greek exit would put pressure on Ireland
Earlier, the Minister for European Affairs Lucinda Creighton has said a Greek exit from the euro would place huge pressure on other countries to exit the currency.
She said it was the biggest test we will ever face in the currency union and said she believed we could meet it.
"If Greece were to exit today, tomorrow morning the markets would be circling around Ireland and other bailout countries, saying when are they going to exit?" she said.
"So we need to think very carefully about the implications, not just for Greece, but the rest of the euro zone countries," she stressed.
"We have to have a strong durable currency- this the biggest test we will face in our currency union," the Minister said.
Speaking on RTÉ radio, she said "I believe we can meet it, but we have to show solidarity with Greece and the Greek government has to play its part."