Drugmaker Novartis aims to dispose of a 13.5 billion Swiss franc ($13.8 billion) stake in its local rival Roche and has already hired banks to support the selling process, a Swiss paper reported on Sunday.

The world's biggest prescription drugmaker started building up the stake - worth 33 per cent of Roche's voting shares - as a basis for a possible merger more than a decade ago, but the plan never materialized.

Novartis plans to sell the stake in a so-called order book process, having banks collect purchase offers within a predefined price range from selected investors, weekly Sonntagszeitung said, citing board and banking sources.

A Novartis spokesman declined to comment on the report. – Reuters