The current bailout plan for Greece was already «very accommodating», he told Germany's Welt am Sonntag newspaper on Sunday.
Inspectors from the EU, European Central Bank and International Monetary Fund are visiting Greece to decide whether to keep it hooked up to a 130-billion-euro lifeline.
Greece has fallen behind targets agreed as conditions of its bailout deal, mainly due to three months of political limbo as it struggled to form a government after two inconclusive elections but also because of resistance to reforms from unions and other interests.
"I cannot see that there is any room left for further concessions,» Schaeuble said. «The problem did not arise because the programme had faults, but rather because Greece did not implement it fully enough,» he said.
He added it was not helpful now to speculate about giving Greece more time or more money.
"It is not a question of generosity. The question is rather, is there plausible way for Greece to manage this."
He also ruled out a further debt writedown for Greece, when asked whether interest could be waived on euro zone bail out loans to Greece or the European Central Bank could waive interest on its Greek debt holdings.
"We have just pushed through a large debt writedown of more than 50 percent with private creditors. I campaigned more for this than many others, and the central bank is independent,» he said.
Asked whether the German state development bank (KfW) could take a writedown on its loans to Greece, Schaeuble said, «The largest German creditor at the first writedown was the state bad bank. We have already participated. It makes no sense to make such a move every half a year. It only destroys trust."
Last September the bad bank of nationalised mortgage lender Hypo Real Estate pledged to roll over almost 1 billion euros ($1.4 billion) of Greek debt, making it the first German institute to quantify its commitment to a second bailout of Athens.
Schaeuble slammed those, including politicians within Germany's centre-right coalition, who have spoken openly about a possible Greek exit from the euro.
If you want to restore calm on markets then you should not «feed them with speculation.»