The Petrobras affair – in which top executives have been accused of colluding with construction companies to inflate contracts and bribe politicians – has set off several red flags at Swiss financial institutions, said Federal Office of Justice spokeswoman Nathalie Guth.
A probe by the federation's attorney general has revealed that "the Swiss financial centre has been seriously affected by the scandal".
"Numerous persons and companies that have been charged or indeed already convicted in Brazil conducted suspicious transactions involving accounts in Switzerland," she added.
Guth confirmed that specific allegations centred on the firm Construtora Norberto Odebrecht SA (BTP Odebrecht) as well as "associated companies and persons".
"Based on the findings made so far, it is suspected that companies in the ODEBRECHT group paid bribes via accounts in Switzerland into accounts held by former Petrobras directors, also at Swiss banking institutions," she said.
The Swiss attorney general held meetings with his Brazilian counterpart in March, with the two agreeing to cooperate in the probe.
Specific requests for cooperation have been made in connection with the allegations against BTP Odebrecht, including questioning suspects living in Brazil and procuring company documents, the justice ministry further said.
The Swiss opened their own inquiry into Petrobras in April of last year, with authorities vowing to crackdown on the number of suspicious transactions that move through the country's banks.
The first sentences against businessmen caught up in the Petrobras scandal were handed down on Monday in a Brazilian court.
Former Camargo Correa construction company CEO Dalton Avancini and another top former executive, Eduardo Leite, were sentenced to 15 years and 10 months prison.
The long-reach of the Petrobras scandal has shaken Brazil's government and left President Dilma Rousseff's Worker's Party increasingly vulnerable.
Last week, Brazilian police raided the homes of several politicians, including former president Fernando Collor de Mello, confiscating three luxury cars.
Some 250 police officers participated in the raid across seven states which was authorized by the Brazil's Supreme Court.
Rousseff has vigorously denied any link to the corruption, vowing that she will complete her term in office, despite plunging poll numbers and the widening scandal at the state oil firm.