The LG Optimus G.

Voice-activated camera ... the LG Optimus G.

LG has unveiled its latest high-end smartphone packed with powerful hardware upgrades, as the struggling South Korean firm tries to win market share from Apple and Samsung in the crucial holiday quarter.

LG's handset business, which was slow to move into smartphones and has largely failed to win consumers from sector leaders Apple and Samsung, hopes the new 'Optimus G' will also help it compete against Google's Motorola, Taiwan's HTC and China's ZTE and Huawei.

LG's Optimus G, which uses Google's Android operating system, will go on sale next week in South Korea for 1 million won ($AU855), and later in Japan and the United States. It is planned for release in Australia early next year.

The Optimus G boasts a 13 megapixel camera which a user can instruct to take snaps by talking to it, plus a 4.7-inch screen with a sharper picture quality than both the iPhone and Samsung's Galaxy S III.

Powered by Qualcomm's quad-core Snapdragon processor, the Optimus G will work on superfast mobile networks and be able to carry out several functions at once, such as showing a television broadcast and simultaneously sending text messages or searching the web.

Among its rivals are the Droid Razr models unveiled by Motorola earlier this month, and Lumia 920, a flagship handset made by Nokia and Microsoft which uses the latest Windows Phone operating software.

Apple unveiled its iPhone 5 last week, and said it had booked orders for over two million iPhone 5 models in the first 24 hours it was on sale, evidence of stronger than expected demand for the new model ahead of the October-December holiday quarter.

Reflecting expectations that the new model will help LG turn around its money-losing smartphone business, LG stock has risen 20 per cent in the past three months, beating a 7.8 per cent rise in the wider market and Samsung's 8 per cent rise.

Reuters