"We believe the banks, which are looting people, are behind this," he said referring to Finance Minister AMA Muhith's recent remark that the country's banking sector was in shambles.
"On behalf of the BNP, I want to say that those who have transferred billions illegally will be brought to book one day," said Rizvi, a senior joint secretary general of the main opposition party outside parliament.
He was speaking at a press conference arranged in the aftermath of the report 'Banks in Switzerland 2016' released on Friday.
Zurich-based Swiss National Bank or SNB published the report on Thursday with the data that deposits by Bangladeshis in Switzerland's banks rose by about 20 percent year-on-year in 2016.
The amount rose to 661.96 million Swiss francs or Tk 55.86 billion in 2016 from 550.85 million francs in the previous year, according to the SNB.
"The government has zero control or monitoring to prevent money laundering," Rizvi said.
The lack of investment opportunities and poor fund management have encouraged money laundering, added the leader.