Reforms from global regulators to prevent banks rigging market benchmarks like Libor again have stopped short of heeding U.S. calls for a more radical response to cleaning up the sector.

The guidance from the International Organisation of Securities Commissions (IOSCO) on Wednesday marks the first attempt to forge a global approach and avoid national initiatives from contradicting each other.

It follows public outrage after UBS , Barclays and RBS were fined $2.6 billion in total for manipulating the London Interbank Offered Rate or Libor.

IOSCO said the data used to construct a benchmark should be based on prices, rates and indices from an active market but this "does not mean that every individual benchmark determination must be constructed solely from transaction data".

Some U.S. regulators have called for benchmarks to be based only on market transactions while others say this is not always possible such as when markets dried up in the financial crisis.

The watchdog, comprising regulators from the world's main securities markets, said it will check within 18 months if its members are applying the guidance, which is legally non-binding.

(Reporting by Huw Jones, editing by Chris Vellacott)