The owner of leading Brazilian shrimp restaurant chain Coco Bambu is under investigation by federal police in the South American nation looking into a group of business leaders calling for a military coup should former President Luiz Inacio Lula da Silva be elected in October.

Businessman Afranio Barreira Filho was among those targeted on Tuesday in raids by federal police as they conducted eight search warrants in five states on the orders of Supreme Court Judge Alexandre de Moraes, who took office as head of Brazil's top electoral court last week.

Barreira Filho and prominent Bolsonaro supporter Luciano Hang, the billionaire founder of department store chain Havan, were targeted along with Multiplan shopping mall operator Jose Isaac Peres and Meyer Joseph Nigri, the chairman of construction firm Tecnisa.

Ivan Wrobel from building firm W3, Jose Koury of Barra World Shopping, wetsuit company boss Marco Aurelio Raymundo and Luiz Andre Tissot from furniture maker Grupo Sierra are also named as part of the operation.

In a statement issued through his lawyers reported by Brazilian media, Barreira Filho said the operation was "politically motivated and based on false reporting."

Coco Bambu, founded in 1989, has 64 outlets across Brazil billing itself as the largest seafood restaurant chain in the country, according to its website.

In addition to shrimp items, menus offer an extensive range of seafood dishes including tilapia, lobster, mussels and squid. The company's featured item is shrimp moqueca, a traditional Brazilian stew similar to curry.

Campaigning for the election, expected to be held over two rounds, is moving into full swing in Brazil.

Trailing in the polls, incumbent far right President Jair Bolsonaro has suggested he may not accept the election result, casting doubt on the country's electronic voting system, even though he was elected via electronic ballot box in 2018.

Brazil, which is facing a severe economic crisis including mass unemployment and homelessness, has become increasingly politically polarized in recent years.

Bolsonaro's bitter rival for the presidency, known commonly known as "Lula," presided over a boom period for Brazil from 2003 to 2010, building on the foundations of economic stability created by his predecessor Fernando Henrique Cardoso.

Lula, a veteran left winger, was himself imprisoned in 2018 as part of a corruption probe, only for his conviction to be later quashed leaving him free to run in October.