* Anti-euro party says it's not populist or right-wing
* Puts on sober face at first Berlin news conference
* Could siphon votes off Merkel in September vote
By Sarah Marsh
BERLIN, March 18 (Reuters) - Leaders of Germany's new anti-euro party took their nascent campaign to Berlin on Monday, keen to reassure potential voters that they are neither populist nor extremist and have come up with a considered plan to bring back the Deutschmark.
The "Alternative for Germany" has been denounced by the country's mainstream parties as an irrational group of scaremongers, keen to profit from anxiety over the growing cost of euro zone bailouts in Europe's paymaster.
But the leaders of the new movement, headed by economist Bernd Lucke who until 2011 was a member of Chancellor Angela Merkel's Christian Democrats (CDU), tried to present a more sober face and distance themselves from other parties in Europe that mix their euroscepticism with unabashed populism and anti-immigration platforms.
"The return to national currencies is our aim, but we do not want to pull out of the euro overnight and go back to the Deutschmark in contravention of treaties," Lucke, a 50-year old father of five dressed in a grey suit and tie, told a room packed full of reporters.
"I reckon it would take a gradual process of about five years to dissolve the euro zone."
The three-year old euro zone crisis has led to the rise of populist movements across the bloc.
Comic-turned-activist Beppe Grillo and his Five Star Movement emerged as a surprise force in Italy's election last month. And 80-year-old car parts magnate Frank Stronach is threatening to upend an Austrian election in the autumn.
A taboo on nationalism in politics, rooted in atonement for the crimes of the Nazis, has so far kept a lid on such trends in Germany, although many voters here are tiring of the perceived cost of the single currency.Ÿ
Germany's AfD, led mostly by greying academics and besuited business figures such as the former head of Germany's industry association Hans-Olaf Henkel, insist they are neither populist nor right-wing.
On Monday, they denounced Europe's new bailout plan for Cyprus, which sparked a backlash because it would force losses on guaranteed bank deposits, as "dangerous" and a breach of trust.
"We feel we have a broad wave of support," said spokeswoman Frauke Petry, a 37-year-old entrepreneur and mother of four who has been awarded Germany's order of merit.
She said the party was luring people from across the political spectrum but above all from Merkel's conservatives and her Free Democrat allies (FDP).
Ulrich Blum, a prominent economist and AfD supporter, said the party had considered hijacking the FDP, a pro-business party, before realising it would not be able to push its eurosceptic agenda effectively.
The FDP's most prominent eurosceptic, Frank Schaeffler, was dropped from the party leadership earlier this month. This weekend a regional FDP leader defected to the AfD.
The AfD, which has just 2,700 formal members, says it rejects membership applications from people deemed extremist. Its party programme includes a section on integration policy, stating that Germany "needs immigrants who are qualified and willing to integrate".
The AfD also considers itself pro-European, albeit anti-euro, and has expressed solidarity with Britain's Prime Minister David Cameron, who wants to shift responsibilities from Brussels back to the EU member states.
Eurosceptic parties have made little headway in the past in a country that regained its political stature after World War Two through its membership of Europe, although opponents of the bloc's bailouts have emerged in mainstream parties like Merkel's CDU, their Bavarian sister party the Christian Social Union, as well as the FDP.
The grandson of Konrad Adenauer, Germany's first post-war chancellor, made headlines last year when he quit the CDU to join the Bavarian "Free Voters" party, which opposes bailouts but has stopped short of calling for an end to the euro.
Polls in recent weeks have shown that roughly one in four Germans would consider backing a party that wanted to take Germany out of the euro.
Pollsters said they did not expect the AfD to make it above the 5 percent threshold needed to enter parliament in September as it was a single-issue party, but it could still become a threat to Merkel's re-election chances if it siphons off votes from her conservative bloc.
"All incremental increases in their votes will eat into the support for the governing parties, which could have a real impact on the elections given what a tight race it is expected to be," said David Marsh, author of books on Germany and the euro.
Polls show Merkel's conservatives well ahead of their opposition rivals the Social Democrats (SPD), but their FDP allies are struggling, putting coalitions from the centre-left and centre-right neck-and-neck.
Pollsters said the AfD may also scoop up protest votes from those frustrated with politics.
Lucke's party took its name "Alternative for Germany" in response to repeated claims by Merkel's government that there was no alternative to bailing out countries like Greece, Portugal and Ireland.
Even the opposition SPD and Greens have refused to challenge Merkel's rescue policies.
"You don't have any opposition in the Bundestag," said AfD spokeswoman Dagmar Metzger. "The last few aid packages were simply nodded through, and that is not what we want, we want an opposition in this country and a voice once more for those people who aren't being heard."