Galaxy Round -- a 5.7-inch concave handset that fits the curve of a user's palm -- has hit stores in South Korea but Samsung did not say when the new phone will be available globally. 

Curved screens -- billed as lighter and thinner than current display panels -- are at a nascent stage in display technology, which is shifting towards flexible panels that are bendable or can even be rolled or folded. 

The new phone -- powered by Google's Android system and featuring a 2.3 GHz quad-core processor --is priced at about 1.08 million won ($1,000), Samsung said. 

"The display (of Galaxy Round) is ergonomically shaped to fit the curve of a hand and comfortably embrace an ear and cheek during a phone conversation," SK Telecom, the country's top wireless operator, said in a statement. 

The new phone allows users to check information such as missed calls, text messages, remaining battery life and the current time and date more easily when the screen is locked. 

When listening to music, users can switch between songs on a playlist by placing the phone on a flat surface and pressing down on the left or right side to tilt the device, which automatically detects the movement. 

The curved screen is made of plastic, instead of the glass that is commonly used in smartphones, and as a result the handset is slightly lighter. 

Samsung said the phone weighs 154 grams (0.33 pounds), 10 percent less than the firm's similar-sized Galaxy Note III oversized smartphone. 

"This certainly is not a ground-breaking, game-changing product," one tech blogger said in a review. 

"But it fits quite nicely in my hand... and the images look slightly deeper when seen on a curved screen," he said. 

The latest device arrived as global smartphone makers vie for growth in the increasingly competitive market. 

Samsung -- the world's top maker of smartphones and mobile phones in general -- in January unveiled the prototype of a bendable display called "Youm". 

Samsung's smaller rival LG said last week it had started mass production of curved display panels for smartphones and is reportedly set to unveil its own curved smartphone this month.

But companies still face a major challenge in making other handset components -- such as batteries -- that can bend with the rest of the unit. 

Curved displays are already commercially available in large-screen televisions offered by companies including Samsung and LG. 

The displays are supposed to offer a more immersive viewing experience but are significantly more expensive than standard screens.