Samsung Electronics is kicking up its competition with Apple with its new Galaxy S 4 smartphone, which has a larger, sharper screen than its predecessor, the bestselling S III.

Samsung revealed the phone Thursday at an event at New York's Radio City Music Hall. The Galaxy S 4, which crams a 12.5-centimetre (5-inch) screen into body slightly smaller than the S III's, will go on sale globally in the April to June period.

Samsung didn't say what the phone will cost, but in the U.S. it's expected to start at $200 US with a two-year contract.

In the last two years, Samsung has emerged as Apple's main competitor in the high-end smartphone market. At the same time, it has sold enough inexpensive low-end phones to edge out Nokia Corp. as the world's largest maker of phones.

The Galaxy line has been Samsung's chief weapon in the smartphone fight, and it has succeeded in making it a recognizable brand while competitors like Taiwan's HTC Corp. and Korean rival LG have stumbled. Samsung has sold 100 million Galaxy S phones since they first came out in 2010. That's still well below the 268 million iPhones Apple has sold in the same period, but Samsung's sales rate is catching up.

Research firm Strategy Analytics said the Galaxy S III overtook Apple's iPhone 4S as the world's bestselling smartphone for the first time in the third quarter of last year, as Apple fans were holding off for the iPhone 5. The iPhone 5 took back the crown in the fourth quarter.

One way Samsung and other makers of Android phone have been one-upping Apple is by increasing the screen size. Every successive generation of the Galaxy line has been bigger than the one before.

The S III sported a screen that measures 12 centimetres (4.8 inches) on the diagonal, already substantially larger than the iPhone 5's 10-centimetre (4-inch) screen. The S 4's screen is 56 per cent larger than the iPhone's.

In a Wednesday interview, Apple's Phil Schiller declined to discuss whether Apple is considering enlarging the screen on the next model of the iPhone, which is expected to be released later this year. He said Apple remains confident that the iPhone 5 is the most useful and elegant smartphone available, hailing it as "the most beautiful consumer electronics device ever created."

Samsung believes the S 4 will set the new standard.

Apart from the larger screen and upgraded processor, the S 4 has a battery that's 20 per cent larger than that of the S III. Samsung didn't say if that translates into a longer battery life -- the added capacity might be gobbled up by the bigger screen or other internal changes.

The S 4 comes with a built-in infra-red diode, so it can control an entertainment centre as a universal remote. This is a feature that has showed up in Android tablets before.

The S 4 comes with several new technologies intended to help users interact with the phone. For instance, the screen now senses fingers hovering just above the screen, and some applications react.

The Mail application shows the first few lines of an email when a finger hovers above it in the list, and the Gallery application shows an expanded thumbnail.

Users can control some other applications by making gestures in the air above the phone. In the browser, you can command the screen to scroll up by swiping from top to bottom a few inches from the phone.

The Camera application can now use both the front and rear cameras simultaneously, inserting a small picture of the user even as he's capturing the scene in front of him.

When several S 4s are in close proximity, they can link up to play the same music, simultaneously — perfect for headphone dance parties.