By Se Young Lee

SEOUL (Reuters) - Samsung Electronics Co is bringing forward the launch of a key premium smartphone model, a person familiar with the matter told Reuters on Friday, as the South Korean tech giant seeks to revive sales after a sluggish second quarter.

The world's top smartphone maker will launch a new version of its Galaxy Note phablet in mid-August, the person said, declining to be identified due to the sensitivity of the matter. Previous versions, such as the Note 3 and 4, typically launched in September.

A Samsung spokeswoman declined to comment.

The mid-August launch will likely put the new Note smartphone model on the market ahead of arch-rival Apple Inc's next iPhones. The U.S. company is preparing for its largest initial production run for new phones so far by the end of the year, the Wall Street Journal reported earlier this week.

Samsung is seeking to rebound from a disappointing 2014, when its annual profit hit a three-year low as smartphone earnings slumped. Though Samsung's earnings are recovering, its second-quarter guidance of a 6.9 trillion won ($6.11 billion) operating profit fell short of market expectations following a supply shortage for the curved-screen version of its flagship Galaxy S6 smartphone.

"I don't know how much the earlier launch will help boost the company's average selling price for smartphones, but this suggests that Samsung will work hard to maintain its market share for the high-end market," said HDC Asset Management fund manager Park Jung-hoon.

(Reporting by Se Young Lee; Editing by Miral Fahmy and Kenneth Maxwell)