LONDON- OPEC expects oil inventories to drop by about 400 million barrels in 2021 in the latest supply and demand outlook being reviewed by a technical meeting on Tuesday, two OPEC+ sources said.

The figure, similar to the implied 2021 stock draw of 406 million barrels seen a month ago by OPEC, is part of what one of the OPEC sources called a "healthy" supply and demand balance for 2021.

OPEC+ experts, the Joint Technical Committee, are meeting on Tuesday ahead of a ministerial meeting on Thursday to decide oil output policy.

(Reporting by Alex Lawler Editing by David Goodman ) ((alex.lawler@thomsonreuters.com; +44 207 542 4087; Reuters Messaging: alex.lawler.reuters.com@reuters.net))