Fourth quarter profit has fallen at Hyundai Motor, after sales of Sonata sedans declined and a stronger won eroded overseas earnings from exports.

Net income dropped 22% to 537 billion won, or $573m, in the three months to the end of December, from a revised 691bn won a year earlier, the Seoul carmaker said, according to a Bloomberg News report. Sales reportedly fell 6.6% to 7.58 trillion won from 8.12 trillion won.

The news agency noted that the won climbed to a nine-year high in the quarter, hurting the carmaker's earnings by cutting money received from and making vehicles more expensive overseas. By contrast, Toyota Motor and other Japanese carmakers are benefiting from a weaker yen, making their cars more competitive, the report added.

"There's no positive news for Hyundai this year," Hyun Hye Jung, an analyst at Woori CS Asset Management in Seoul, told Bloomberg News, adding: "The won is exerting pressure, sales in the US are weak and margins in China are being squeezed because of fiercer competition."

The won was 10.5% higher against the dollar in the fourth quarter compared with a year earlier. In contrast, the Japanese yen was 0.5% weaker against the dollar, Bloomberg said.

A stronger won increases the price of exports, which accounted for about 57% of the carmaker's sales in the first nine months of last year, the report said.

The gain in the won has forced Hyundai Motor to raise the price of its revamped Accent subcompact twice since September last year, making it 5.4% more expensive than Toyota's Yaris subcompact in the United States, Bloomberg News added.

Operating profit, or sales minus administrative expenses and the costs of goods sold, fell 8.6% in the fourth quarter to 307 billion won, Hyundai Motor said, according to the report.