Thousands of demonstrators flooded a German city on Saturday, blocking major roads and disrupting public transport, in a bid to shut down the annual congress of the far-right AfD party.

About 20,000 people flocked to Erfurt in Thuringia state, according to police, to protest against the Alternative for Germany (AfD) party that tops national opinion polls.

The protesters, led by an alliance dubbed "Resistance", blocked routes into the city, with some abseiling from a motorway bridge. Several groups staged sit-in blockades around the city centre.

But most AfD delegates managed to reach the conference centre where the congress began on time.

"It's important to send a signal against the shift to the right," said demonstrator Lene Krug, 19, from Gera, east of Erfurt.

"The AfD is an anti-democratic party that spreads hate."

Another protester, Ella, was among a group who stuck themselves to tram tracks in a city square.

"1933 to 1945 must never happen again," said the 44-year-old, who only gave one name, referring to the period when the Nazis were in power.

"The democratic parties need to understand that they must impose a ban [on the AfD]."

The early protests were largely peaceful.

Minor scuffles were reported between protesters and the thousands of police deployed for the congress.

News weekly Der Spiegel quoted internal police documents as saying that up to 2,500 protesters were expected to come prepared for violence.

The AfD's rapid rise has unnerved many Germans, who feel they have a special duty to fight far-right politics given Germany's dark Nazi past.

Some have seen a deliberate provocation in the AfD holding its Erfurt conference on the 100th anniversary of a Nazi conference in nearby Weimar, a charge the AfD denies. (AFP)




Edited by Tony Sabine