The Galaxy S3 boasts a 4.8-inch screen (12.2cm), 22 percent larger than the Galaxy S2, the hugely popular predecessor that helped the company overhaul Nokia as the world leader.
Despite the larger screen, Samsung says the phone is not much larger than its predecessor due to its smaller frame.
Other new developments include “intelligent camera features” which use face recognition technology and improved voice-activated controls.
The new model also uses the Android operating system, and its performance in the marketplace is perceived to be crucial to the success of the Linux-based system.
“The importance of the Galaxy S3 to Samsung cannot be underestimated,” Adam Leach, principal analyst at Ovum, told the BBC.
“The company has built its reputation on producing the must-have Android smartphone and in the process has become the poster child for the Android platform.”
The handset goes on sale in Europe in May to be followed by launches in Asia, the Middle East and Africa.
Samsung last week reported a record net profit of 5.05 trillion won ($4.44 billion) in the first quarter, thanks largely to strong smartphone sales.