A growing number of lawmakers are threatening to dent German Chancellor Angela Merkel's authority a year before an election by rebelling in a Bundestag vote on help for near-bankrupt Greece.
Greece's international creditors are due to announce concessions next month, likely to include an additional two years for Athens to implement its austerity targets and reduce its debt pile, resulting in additional costs of billions of euros.
Any such changes must be voted on by German lawmakers. Rebels from Ms. Merkel's centre-right coalition, who have warned consistently of throwing good money after bad, say their stance has been vindicated and expect others to join them in voting "Nein."
"I believe there are many more doubters than before because everything we were led to believe, for example that Greece would only get aid in return for sticking to strict targets, simply hasn't been the case," said Veronika Bellmann, a lawmaker from Ms. Merkel's Christian Democrats (CDU) in the state of Saxony.
The opposition Social Democrats have backed Ms. Merkel's euro zone policy in Bundestag votes, although the Chancellor has always had enough support from within her own ranks to pass legislation. A significant rebellion, and the need to rely on outside support, would damage her reputation as a strong steward in a crisis and lose her political capital with voters.
Ms. Bellmann supported the first Greek bailout but has voted 'no' in subsequent votes in the Bundestag, and she said she enjoyed strong support from her constituents who are alarmed at Germany's increasing liabilities to Greece.
"We have been waiting for a report from Greece's international lenders, which is expected to say that Greece still can't meet its targets even after two bailouts, and a pledge by the European Central Bank to do all it can."
Jens Ackermann, a member of the Free Democrat Liberals (FDP), Ms. Merkel's junior coalition partners, said: "We need to consider each vote on a case-by-case basis … but I see my fears confirmed on Greece.
"With each vote there have been more and more rebels and I expect that the number will rise this time as well. Germany doesn't have the power to shoulder endless rescues."
In June, 300 of Ms. Merkel's 330 coalition lawmakers approved the euro zone's permanent bailout scheme and new budget rules, down from the 304 deputies who had endorsed a second bailout for Greece in February.
In September, 2011, only 13 deputies had defied Ms. Merkel in a vote to boost the euro zone rescue fund. The Bundestag has 620 seats.
Ms. Merkel's stance toward Greece has softened since her visit to Athens at the start of the month, which convinced her Greek Prime Minster Antonis Samaras is trying his best to implement reforms despite the headwinds of a deep recession.
Her parliamentary floor leader Volker Kauder tried on Monday to ease rebel frustration and urged lawmakers to wait for the report by the troika of international lenders due in November. A vote is likely to follow in December.
"We will evaluate this in order to discuss it in the Bundestag," he told German's Bild newspaper, adding Mr. Samaras had made more progress than any of his predecessors.
Mr. Kauder acknowledged the German government could face difficulties this time around. "We have always got our own majority when it was necessary. But I know that the situation will not be easy in the bloc."
The popularity of Ms. Merkel's conservatives stands at its highest level in more than three years, according to an opinion poll that showed no outright winner in next year's election.
The closely watched Politbarometer for ZDF TV also showed a 48 per cent of Germans believe Greece should remain in the euro zone while 44 per cent believe the country should exit the common currency. The 48 per cent is up two points from the previous poll. Earlier polls had showed a large majority in favour of Greece leaving the euro zone.
However, that trend could change if Greece needs further significant aid measures, including a debt restructuring.
Bild said in a column on Monday: "A country that cannot pay back its debts to its European partners has simply no business being in the euro. If it does in fact come to a second debt haircut, then Greece must leave the euro."