UPDATE 1-COMCO opens investigation into Swatch Group

* Swatch Group initiated investigation

* Looking for ways to reduce deliveries to third parties

(Adds detail, background)

ZURICH, June 8 (Reuters) - Swatch Group (UHR.VX) said on Wednesday it had initiated an investigation by Swiss competition authorities to find a way of reducing deliveries of mechanical watch parts to third parties.

Swatch, the world's largest watchmaker, said the investigation sought a mutually agreed solution to allow it to reduce gradually its deliveries of mechanical components to third parties in the interest of the entire watch industry.

Swatch Group's manufacturing unit ETA, formed from a number of independent factories set up at the end of 18th century, is the lifeblood of the whole Swiss watch-making industry. It makes movements fitted in about 80 percent of Swiss watch brands. Switzerland's watch brands have become too dependent on Swatch Group and have not invested enough in engineering, preferring to splash out on marketing campaigns featuring sports stars and actors, industry analysts say.

Swatch, best known for its colourful plastic Swatch watches, also owns higher-end brands such as Breguet, Blancpain and Omega. (Editing by Dan Lalor)