The anti-immigrant and eurosceptic Alternative for Germany (AfD) is surging in popularity in the eastern state of Saxony, the Infratest dimap polling agency reported on Tuesday.
The poll of 1,000 respondents was conducted by phone last week, before the street protests that followed a fatal weekend stabbing in Chemnitz, the third-largest city in the state.
The stabbing has acquired a racial dimension and sparked two days of protests and counterprotests in the eastern city.
The AfD is now polling second on 25 per cent, up 15 percentage points since the 2014 elections.
Chancellor Angela Merkel's Christian Democrats (CDU) are holding on as the most popular party on 30 per cent, but this represents a dramatic fall of 9 percentage points.
The state's governing coalition between the CDU and the Social Democrats (SPD) - which mirrors that at federal level - no longer has majority support, with the SPD down one percentage point at 11 per cent.
Saxony will hold state elections in a year's time.
The AfD won over 12 per cent in national elections last September, entering the national parliament, the Bundestag, for the first time.
