AMSTERDAM, May 31 (Reuters) - Dutch specialty chemicals maker DSM on Tuesday said it would merge with its Swiss peer Firmenich in a deal involving shares and cash, to become a leading supplier of food ingredients and beauty and well-being products.

The companies said the merger, expected to be finalised in the first half of next year, could lead to an organic sales growth of 5% to 7% per year and annual cost savings of 350 million euros ($376.15 million).

DSM shareholders would own 65.5% of the new Dutch-Swiss group, while current owners of Firmenich will ownn the rest of the shares and wil receive 3.5 billion euros in cash.

($1 = 0.9305 euros) (Reporting by Bart Meijer; Editing by Kim Coghill)