LG Electronics launched Tuesday its new flagship smartphone which will have to compete against a flurry of new products from rivals Apple and Samsung who currently dominate the global market.

The South Korean electronics giant said the new gadget -- called Optimus G -- would hit domestic stores next week before sales begin in Japan in October and other regions including North America in November.

The launch comes days after Apple unveiled the much-anticipated iPhone 5 which garnered more than two million orders in just 24 hours.

Samsung Electronics, which has sold more than 20 million of its Galaxy S III smartphone launched in late May, is set to introduce the newest version of its popular oversized Galaxy Note smartphone in the market soon.

"It's inevitable for these flagship products to compete head-to-head ... but we are expecting very significant and surprising figures for this product," Park Jong-Seok, head of LG's mobile unit, told reporters.

He refused to elaborate on the sales target.

The new phone -- powered by Google's Android software -- is equipped with a new quad-core processor made by Qualcomm that helps run applications about 40 percent faster than existing quad-core processors.

About 13.2 centimetres (5.2 inches) long, 6.9 centimetres wide and featuring a 4.7-inch touchscreen, Optimus G allows users to zoom in on moving video images and takes photos by recognising voice words like "cheese" or "smile."

It can also simultaneously display overlapped images of two applications, for instance allowing users to exchange chat messages or search the Internet while watching a video played in the background.

"Smartphone users spend a growing amount of time watching videos, so this can be a really helpful feature," Chang Ma, vice president of marketing in LG's mobile unit, said.

The new gadget also automatically adjusts bell sounds based on noise level around users to help prevent missed calls, he added.

The world's number two flat-screen TV producer and the fifth biggest phone maker, LG has struggled for years in the rapidly-growing smartphone market.

The firm's cellphone business -- a segment LG has flagged as a strong pillar of growth -- bled for years as sales of its Optimus smartphone series lagged far behind Apple's iPhone or Samsung's Galaxy S phones.

LG's mobile unit once showed signs of recovery by posting profits in the fourth quarter of 2011 and the first quarter this year but swung back to a loss in the second quarter.

The reversal was blamed on high marketing costs for promoting its new handsets and squeezed margins due to the weaker euro.

Park said the firm's earlier goal to sell 80 million mobile phones this year was still valid, with the Optimus G helping to drive sales beginning in the third quarter.