EU-IMF auditors holding loan talks in Athens were heckled by protesters on Tuesday and a man was briefly detained after throwing coins at the IMF mission's chief, police said.
A few dozen protesters, including ministry staff included in an unpopular job furlough scheme, blocked the entrance of the finance ministry where the auditors began talks with officials.
A man was briefly detained for throwing coins at the car of IMF mission chief Poul Thomsen, a member of the three-man auditing team that is evaluating the pace of Greek reforms.
He was later released without charge, the police said.
After a meeting with the finance minister, members of the so-called troika -- the EU, IMF and the European Central Bank -- were taken out of a side entrance under police guard.
The audit is being held ahead of the finalisation of Greece's budget, and the creditors are expected to push for more unpopular austerity measures to cover a fiscal gap of two billion euros forecast for 2014.
The troika's report is also necessary to unlock a vital one-billion-euro ($1.3 billion) loan instalment.
There is anger in Greece over ongoing cuts in spite of a six-year recession and soaring unemployment, and further outrage that new taxes are being prepared to help meet deficit goals.
A sizeable number of government deputies have protested plans to increase tax on agricultural land, a move that has put pressure on Prime Minister Antonis Samaras.
"This is a negotiation...we should remove the notion that this is a war," Samaras said in a televised interview late on Monday.
"The review mission in Athens is just being restarted today - let's give them peace to work," EU economic affairs commissioner Ollie Rehn said in Brussels.
"The negotiations on fiscal issues with Greece has never been precisely easy, but I don't see they are more difficult than normally - I'm sure we'll be able to find a satisfactory solution," he said.
Unions are holding a 24-hour general strike against austerity on Wednesday, the fifth this year.