Park Jin-young, Samsung's vice president for the mobile business, said the firm expects overall smartphone sales volume to increase in the third quarter from the previous quarter as the firm launches new larger-screen models and new mid-to-low tier products.
The firm also reported a 4 percent fall in second-quarter profit and ruled out a "special dividend" similar to a big year-end payout for 2014. That disappointed investors, pushing its stock lower as pressure grows on Korean firms to return more capital to shareholders.
Samsung's dominance is being chipped away at the low-to-mid end by Chinese rivals such as Huawei Technologies Co Ltd  and in the premium segment by Apple, while some markets show signs of saturation. Researcher TrendForce last week cut its 2015 global smartphone market growth forecast to 8.2 percent from 11.6 percent earlier.
Samsung remained the top smartphone maker in April-June, but shipments fell in part due to an inability to build enough curved-screen Galaxy S6 edge handsets, analysts said. The firm said its mobile division will launch new larger-screen phones in the third quarter but may not be able to improve earnings.
Samsung's mobile business booked a 38 percent decline in April-June operating profit at 2.76 trillion won. It expects smartphone shipments to rise in the third quarter from the second, but said average selling prices could fall due to price adjustments for S6 models aimed at boosting sales.
The firm has brought forward the launch of its latest Galaxy Note phone to August from September, while a person familiar with the matter told Reuters that it plans a larger version of the S6 edge. But new iPhones in September would limit Samsung's third-quarter sales growth, analysts said.