* Merkel: need to change euro rules to include forced exit
* Says euro facing its biggest challenge
* Juncker says Europe should copy German debt brake rule
(Releads, adds comments by Eurogroup's Juncker)
By Paul Carrel
BERLIN, March 17 (Reuters) - European rules need to change so that countries that repeatedly break the bloc's economic guidelines can be expelled from the euro zone, German Chancellor Angela Merkel said on Wednesday.
The comments, given in a speech to the Bundestag lower house of parliament, represent the first explicit call from a European leader for such a change, although Merkel's finance minister Wolfgang Schaeuble broke a taboo earlier this month and urged similar steps.
"In the future we need an entry in the treaty that would make it possible, as a last resort, to exclude a country from the euro zone if the conditions are not fulfilled again and again over the long term," Merkel said.
She also said the Greek debt crisis had landed the euro with its biggest challenge ever but a quick fix by other members of the currency club was not the right strategy.
"The euro is facing the strongest challenge it has ever had to cope with," she said. "The (solution) ... can only be one we find with regard to the long-term stability of the euro.
"A quick act of solidarity is definitely not the right answer. Rather, the right answer is to seize the problem at the roots ... therefore there is no alternative to the Greek savings programme," she added in a speech.
Schaeuble has advocated the creation of a European Monetary Fund (EMF) which could support troubled members of the euro zone but coupled that proposal with a suggestion that members of the 16-nation currency bloc be allowed to leave.
The idea has won tentative backing from Merkel and other countries, but is seen as a longer-term solution that would require changes to the EU's Lisbon Treaty.
"Wolfgang Schaeuble has not made proposals for Greece," Merkel said. "Wolfgang Schaeuble has made proposals so that the IMF wouldn't need to be called in potential situations for which that might now have to be the way out."
Some members of the European Central Bank have come out against the EMF idea, a stance Bundesbank chief Axel Weber reiterated on Wednesday.
"I don't think we should be too inventive in always inventing new tools, we have a set of good tools, what we need to do is harden those tools," Weber said, referring to the EU's Stability and Growth Pact, which sets debt and deficit limits.
"We need to have surveillance processes, we need to have a monetary or fiscal expenditure programme way before excessive fiscal deficits emerge," he added.
The EMF idea has emerged as Greece battles to persuade financial markets it can control its debt burden with austerity measures including more than 2 billion euros ($2.75 billion) in budget cuts and an increase in value added tax (VAT) to 21 percent.
Weber said a self-help plan was the right way to go. [ID:nLDE62G0JG]
"What Greece needs to be doing, and what they have done, is they have put forward a credible, and in my view quite substantial plan, on how they will reduce deficits," he said.
Eurogroup Chairman Jean-Claude Juncker said the euro zone will have to consider adopting a rule like Germany's "debt brake" law to ensure countries keep their budget deficits in check, but he did not spell out which sanctions rule-breakers should face. [ID:nLDE62G281]
"I have great sympathy for the German debt brake," said Juncker, who chairs monthly meetings of finance ministers from the euro bloc. "We will also have to consider such a rule or a similar measure in the euro zone."
A new "debt brake" law will force the German government to make substantial reductions in new borrowing from 2011.
Under legislation introduced by Chancellor Merkel's former "grand coalition" government, federal new borrowing will be capped at 0.35 percent of gross domestic product from 2016.
(Reporting by Paul Carrel and Erik Kirschbaum, additional reporting by Sakari Suoninen in Cologne; writing by Noah Barkin; Editing by Ruth Pitchford)