BRUSSELS, Nov 9 (Reuters) - The European Commission will host technical experts from the Group of Seven (G7) over three days next week in Brussels with the aim of hashing out a final plan for a ban on Russian-origin diamonds, sources familiar with the matter said.

The European Union is a member of the G7 along with member states France, Germany and Italy. The Commission did not immediately comment on the meeting.

The sources said the planned Jan. 1 implementation date was slipping since the talks have dragged, but the G7 was aiming to implement the ban starting in the first quarter of next year.

The Commission is expected to propose its 12th package of sanctions on Russia to member states next week with a focus on cutting Moscow's revenues from diamonds.

An EU diplomat said Belgium's proposal that suggests tracing the diamonds from the rough stage in Antwerp would be closely mirrored in the Commission's proposal.

The G7 has been looking at three other proposals from a French industry group, India and the World Diamond Council.

Antwerp in Belgium is the main hub for the world's rough diamond trade, while India is the centre for polishing diamonds before resale.

Russia's state diamond miner Alrosa has been placed under sanctions by the United States, but not the EU. Major western jewellery brands began shunning Russian diamonds soon after Russia invaded Ukraine in February last year. (Reporting by Julia Payne; Editing by Jan Harvey)