The party Alternative for Germany (AfD), dismissed as populist and irresponsible by its critics, has caused a stir with its demand for the country to ditch the euro currency and return to the Deutschmark.
A new poll by the INSA institute for top-selling tabloid Bild gave the party three percent support, two days after it was formally launched.
The party has argued that Europe's biggest economy is overburdened by helping to bail out its debt crisis and recession-hit southern neighbours in the 17-member currency zone.
The party stresses that it is not nationalistic or anti-immigration.
"The AfD has big potential," the polling institute's chief Hermann Binkert was quoted as telling the newspaper. "Two thirds of Germans reject the multi-billion-euro bailouts."
The poll also gave Merkel's conservative Christian Democrats 39 percent, and five percent to their junior coalition partners, the pro-business Free Democrats. Their main opponents, the centre-left Social Democrats, scored 26 percent, while their preferred partners the Greens party polled 15 per cent.
This gives Merkel's ruling coalition a theoretical lead of 44 against 41 percent over the rival alliance – an edge that, political observers warn, could shrink as smaller parties eat into the support of mainstream parties.