Alice Weidel, one of the AfD's top two candidates in the Sept. 24 election in Germany, said Trump's response to a recent white nationalist rally in Charlottesville, Virginia, had been "completely unnecessary" and she had only a "limited understanding" for it.
"Donald Trump should focus more on policies and less on tweeting and Twitter," Weidel told journalists in Berlin. "If I had a wish list, then I would wish that Donald Trump would focus ... more on cleaning up his own house, and being a little more devoted to his governing responsibilities."
Trump was widely criticised for at first failing to condemn white supremacist groups after a man thought to have neo-Nazi sympathies drove a car into a crowd of anti-racism protesters in Charlottesville, killing a woman and injuring over a dozen other people. Trump had said "both sides" were to blame for the violence and there were "very fine people" at the rally.
Weidel's comments came amid controversy over remarks made by a senior member of her own party, Alexander Gauland - the AfD's other top candidate - who said Integration Minister Aydan Ozoguz, a Social Democrat (SPD) politician born in Germany to Turkish parents, should be "dumped" in Turkey.
Members of the SPD, and Chancellor Angela Merkel's conservatives, rejected Gauland's remarks as racist.
Weidel said that although her party opposed Merkel's 2015 decision which has allowed more than a million migrants into Germany over the past two years, it condemned extremism in any form, whether it came from left-wing, right-wing or Islamic groups.
Founded in 2013 as an anti-euro party, the AfD shifted its focus after the euro zone debt crisis peaked to campaigning against immigration after Merkel's move to open the borders.
It is expected to enter the German parliament for the first time after the September election, although its support has dropped to 7 to 10 percent from a height of around 15 percent in 2016, according to polls.
Weidel, who is openly gay, chafed at a question about whether she was racist, noting that her partner of nearly 10 years, a Swiss filmmaker, also has a Sinhalese background.