Dozens of police in riot gear drove the protesters off Erzsebet bridge, detaining several of the mainly far-right activists calling for the resignation of Socialist Prime Minister Ferenc Gyurcsany.
Pushed back by police, the protesters marched on the main road leading off the bridge in Pest, holding up private cars as well as trams and buses.
Traffic was also interrupted briefly across the Chain Bridge when three men climbed on one of the bridge's pillars.
Around 250 protesters yelled "Gyurcsany get out!" and "He should resign!" but did not resist the advance of police, who used loudspeakers to warn the crowd to disperse.
National Police Chief Jozsef Bence said 54 people had been detained by police, among them several leaders of right-wing groups that had called for Friday's blockade.
Bence said the bridge blockade was considered illegal because it was not reported to police before taking place. He said further protests were expected later Friday.
In Hungary, pre-announced protests are usually allowed by police, unless there is a commanding reason such as an excessive disruption of traffic for them to be banned.
Friday's protest was organized by far-right groups on the 17th anniversary of the infamous "taxi blockade," when taxi drivers used their vehicles to block off traffic on several Budapest bridges and roads across the country for three days to protest a 65 percent rise in gasoline prices.
Numerous protests as well as some violent riots have taken place since Sept. 17, 2006, when state radio broadcast parts of a secret speech by Gyurcsany to party officials in which he admitted the government had lied about the state of the economy to win the April 2006 elections.