Singapore’s central bank is investigating whether banks involved in a S$2.4 billion ($1.75 billion) money laundering scandal have mitigated risks.

The Monetary Authority of Singapore (MAS) will act if its findings show bank control issues.

The issue has raised doubts about whether banks are obeying the city-state’s strict anti-money laundering rules.

Singapore has seen large asset inflows in recent years as wealthy Asians set up family and trust offices to take advantage of incentives.

The MAS has conducted thematic inspections and enhanced due diligence measures.