Brazilian fans and protesters, unhappy over Brazil's 7-1 World Cup defeat against Germany, have taken to the streets of Sao Paulo and burned at least 20 buses, as police ramp up security for Wednesday's semi-final.

Throughout the night on Tuesday, police and fire services reported several attacks on buses in the South American country's largest city.

Most were destroyed when a garage full of buses was set on fire in the southern area of Sao Paulo, the Reuters news agency reported.

According to local authorities, at least 20 buses were destroyed and others were damaged.

Meanwhile, Sao Paulo police increased security for the semi-final between Argentina and the Netherlands.

When Argentina played Switzerland on July 1 in Sao Paulo there were isolated incidents of violence and rioting and police were called in to respond.

"Today our squad has been increased 20 percent because of today's event and because of the high concentration of people during Argentina's last game. We boosted our detail and we will conduct ourselves in the best manner possible as we have in the last days," Hernane Pereria Melete, the police inspector, said.

Brazil were thrashed 7-1 by Germany in a record World Cup defeat, their first loss at home in 64 competitive matches since 1975.

It was also the first time they had lost by six goals in any match since neighbouring Uruguay beat them 6-0 in the Copa America in 1920.