The Asian Development Bank has imposed sanctions on 30 people and 31 firms for "integrity violations", following a 2013 fraud investigation into $1 billion worth of projects it funded, the lender said.
The ADB said it investigated a record 250 allegations of corruption, collusion, coercion and fraud last year, 10 more than in 2012, the bank said in a report published Wednesday
The investigation included six projects operational between 2006 and 2010 in China, Azerbaijan, Pakistan, Nepal and Laos, which were probed for "procurement-related" issues, ADB said in the report.
"Fraud related to work experience, qualifications, and technical and financial capacities of consulting firms or consultants continues to be the most common type of integrity violation reported," the ADB's Office of Anticorruption and Integrity chief Clare Wee said in a statement.
The names and nationalities of the companies and individuals punished, as well as the nature of the sanctions, were not disclosed in the report by the Manila-based ADB. Bank representatives declined to comment further when contacted by AFP Wednesday.
However, ADB sources, who asked not to be named, said companies receiving sanctions would be "blacklisted" and barred from taking part in ADB projects for between three and 10 years.
Sanctions can be imposed on individuals "indefinitely" depending on the circumstances, the sources added.
The allegations investigated included an agricultural project in the Ningxia autonomous region in China that was funded by a $100 million loan and a $4.545 million grant and an Azerbaijan road project backed by an $500 million ADB loan, it said.
Investigators also looked into a Pakistan power transmission project supported by $358.747 million in ADB loans, as well as three smaller projects in Nepal and Laos that obtained $92 million in ADB loans and grants.
The ADB sources said that in extreme cases, the lender also operates under a "cross debarment" system in which it and other multilateral institutions will all enforce each other's blacklists.
The report said 525 entities have been subjected to this type of sanction by the ADB, the World Bank, the European Bank for Reconstruction and Development and the Inter-American Development Bank since 2010.
The ADB lent $9.4 billion in 2012, according to the latest data released by the bank.