LONDON- The Swiss government said on Thursday it had proposed changing the way gold is recorded by global customs authorities to give more information about its quality and use and make the bullion trade more transparent.

All manner of shapes and purities of gold are currently recorded under a single code, known as an HS code, used around the world.

"It is not possible to differentiate in the HS between refined and unrefined gold or between bank grade gold and gold alloys," Switzerland's State Secretariat for Economic Affairs (SECO) said in a statement.

It said it had proposed to the World Customs Organization that traders should add information to import declarations to enable separate recording of mined and banking gold.

This would "improve the traceability of commodity flows, the transparency of statistics and the quality of controls," it said.

Large amounts of gold are mined illegally, smuggled or used to launder money and finance violence. Many governments, companies and banks have stepped up efforts to exclude this metal from the mainstream industry.

Switzerland is the world's biggest precious metals refining and transit centre, exporting gold worth around 60 billion Swiss francs ($65 billion) last year.

SECO said if the World Customs Organization accepted its proposal it would become the international standard from 2027.

It said Swiss customs would require importers to supply the additional information from Jan 1, 2021.

($1 = 0.9253 Swiss francs)

(Reporting by Emma Farge and Peter Hobson; Editing by Bernadette Baum) ((Peter.Hobson@thomsonreuters.com; +44 207 542 0083;))