About 1,400 policemen will be "ready to use force" to maintain law and order on Saturday, Prague Mayor Pavel Bem and the city's top police officers told reporters.
The march had been scheduled to take place Nov. 10, a day after the anniversary of Kristallnacht, the 1938 night of terror when the Nazis attacked synagogues and Jewish homes and businesses throughout Germany and parts of Austria.
The march was banned by Prague and the decision was upheld by a court ruling on Monday.
The event - organized by the Young National Democrats, which is linked to the National Resistance, a neo-Nazi group - was condemned by Jewish leaders as well Czech politicians as an insult to the victims of the Holocaust.
Organizers said the march was meant to protest the deployment of Czech troops in Iraq and pledged to defy the ban.
Prague's Jewish groups had said they planned to gather at several meetings on Saturday to commemorate victims of the Nazi pogrom and be ready, if the march went ahead, to prevent it from going through the Jewish quarter.