South Korean electronics giant enjoyed an increase of 17 per cent in net earnings in the fourth quarter of last year, thanks to strong sales of its smartphones.

In a regulatory filing on Friday, Samsung said its net profit reached 4 trillion won ($3.5 billion) in the quarter to December 2011. In the corresponding period of previous year, the company pocketed a net profit of 3.4 trillion won.

Operating profit climbed 75.8 per cent to settle at 5.3 trillion won in the final three months of last year.

The Suwon, South Korea-based manufacturer did not reveal its own sales figures for the concerned three months, but as per research firm Strategy Analytics’ estimates, it sold around 36.5 million smartphones.

Samsung’s telecoms division generated a record profit of 2.64 trillion won ($2.35 billion) in the fourth quarter, thanks to increased sales of its highly acclaimed Galaxy smartphones.

Samsung is locked in patent battles with Cupertino, Calf.-based gadget maker Apple, which claims Samsung is copying its iPhone and iPad.

To strengthen its position against rivals, Samsung has set aside $22 billion to enhance production of chips and flat screens this year.

Stock in Samsung was up 0.5 per cent at 1.119 million won in Seoul on Friday.