German Finance Minister Wolfgang Schaeuble said a new anti-euro party "can't be taken seriously" and labelled its core demand "economically insane" in comments published on Sunday.
The small Alternative for Germany (AFD) party wants to ditch the euro and bring back the Deutschmark currency. It has called for an "orderly dissolution" of the 17-member eurozone.
Formed only weeks ago, it has scored between two and five percent in a series of polls, five months ahead of elections in which Chancellor Angela Merkel will seek a third term.
Schaeuble told the Focus news weekly that in a narrow election race where every vote counts, "we will also deal with the AFD" and its message.
"We will not do so arrogantly but in the firm belief that a common currency is in Germany's interest," he was quoted as saying. "For Germany, it would be economically insane to leave the euro."
Asked whether he takes the political newcomers seriously, he said: "I want to differentiate: I take seriously the concern people have about their money. But a party that is only against something can't be taken seriously. And it won't succeed in Germany."
Foreign Minister Guido Westerwelle meanwhile warned that "giving up the euro would mean risking the collapse of Europe," speaking to the Bild am Sonntag newspaper.
The AFD, unlike many eurosceptic parties elsewhere, has so far stayed clear of far-right fringe and anti-immigrant rhetoric. It has around 10,000 members now and is busy setting up chapters across Germany.
"Given the enormous wave of support we are seeing, I think it's possible we will get double-digit support," a confident party spokesman, Bernd Lucke, told the Tagesspiegel daily Saturday.
The chief candidate of Merkel's junior coalition partner the pro-business Free Democrats, Rainer Bruederle, was also dismissive about the AFD in comments reported Saturday by newspaper Die Welt.
He called the idea of an alliance with the party "completely absurd" and said the AFD "has not thought the issues through. It lacks positions on almost all important issues."
The party scored five percent in an INSA poll last week, the level needed to enter parliament, but polled at only two percent in another survey. In the latest poll, by public broadcaster ZDF, it stood at three percent.
While its ratings remain low for now, some political observers say that support for the party could steal away crucial votes from Merkel's centre-right coalition in the September 22 vote.
Westerwelle voiced a similar concern, saying "it would be terrible if an anti-European party" could inadvertently help the centre-left opposition snatch victory from the Merkel government.