LONDON, Oct 24 (Reuters) - The London Metal Exchange (LME) is monitoring the levels of Russian metal stored in its system and could take action if it thought there was a problem, its chief executive said, without specifying what it might do.

The 145-year-old exchange launched a discussion paper earlier this month on the possibility of banning Russian aluminium, nickel and copper from being traded and placed in its registered warehouses.

In the paper, the LME provided graphs showing percentages of Russian inventories compared to the total, but since then sources have told Reuters that significant amounts of Russian-origin aluminium has been delivered into the LME system.

LME Chief Executive Matthew Chamberlain told Reuters that the exchange would not provide running updates on whether there had been new flows of Russian metal to LME approved warehouses.

"I can't talk about what the numbers are...but the LME has always monitored these things, and if there were a problem we have the ability to take action," he said in an interview at the start of industry gathering LME Week.

The graphs in the discussion paper showed the proportion of Russian copper in LME warehouses was the highest at slightly over 60%, nickel the lowest at under 5%, and primary aluminium about 15%.

Chamberlain said the key issue revolved around whether participants would shun Russian material next year and whether that would create a problem of "dumping" into the LME system.

"The basis on which we would take action is if it were revealed through the discussion paper feedback that there was a real risk that Russian metal wouldn't be used by consumers in 2023," Chamberlain said.

The LME would prefer that any action it took was underpinned by government sanctions, but it might have to move on its own, he added.

"In that extreme scenario where there weren't sanctions and there was a very clear consensus that Russian metal wasn't going to be consumed by a large swathe of global users in 2023, the discussion paper is where you could see the LME having to take action unilaterally."

He declined to say whether the exchange had held discussions with Russia's Rusal, the world's largest aluminium producer outside China, or the United States government, which is considering restricting imports of Russian metal.

The LME is owned by Hong Kong Exchanges and Clearing Ltd. (Reporting by Eric Onstad and Pratima Desai; Editing by Kirsten Donovan)