The European Central Bank is close to announcing a clampdown on possible abuses by banks of its financial market liquidity-supporting operations, a member of its governing council has indicated.

Yves Mersch, governor of Luxembourg's central bank, said at the weekend that ECB policymakers had agreed a "certain amount" of refinement to the central bank's rules. His comments are the clearest indication yet that the ECB will act on worries that banks are taking advantage of its relatively generous system, possibly building up problems for the future.