As one of Athens’ biggest creditors, the eurozone’s largest economy has banked millions in interest on loans to the heavily indebted state over the last two years alone.
A loan from Kreditanstalt für Wiederaufbau (KfW), the state development bank, has raked in about £350million (€393m) from interest payments since 2010, according to the Süddeutsche Zeitung.
Politicians are now demanding the interest is paid back to Greece.
It comes after Athens recently received a further £7.5bn (€8.5bn) as its latest bailout continues.
Green budget expert Sven-Christian Kindler said: “It may be legal for Germany to make money from the crisis in Greece.
“But it’s not legitimate in a moral sense of solidarity.”
Jens Spahn, parliamentary state secretary in the Federal Ministry of Finance, rebuffed the calls to refund the cash.
He said: “The Federal Government is currently not planning such a referral.”
Germany also benefits from the European Central Bank (ECB)’s bond-purchasing programme in 2012 designed to help crisis hit countries like Greece.