Central bankers should be heavily involved in assessing threats to financial stability, particularly when interest rates are so low, the Federal Reserve's vice chair, Janet Yellen, said on Friday.

It's important for those making monetary policy to keep in mind trends affecting financial stability, Yellen said at a conference on the role of central banks in financial stability, sponsored by the Chicago Fed and the European Central Bank.

Policymakers should be aware that these very low levels of interest rates can potentially touch off a buildup of financial risk in the system, she said.

(Reporting by Ann Saphir)