The stellar rise of Hyundai and affiliate Kia is clearly being watched closely by a top executive at Nissan Motor.

"Should they continue to grow at this speed, Koreans will become a top player in every market in the world and they do have this potential," chief operating officer, Toshiyuki Shiga, was quoted as saying during a visit to Seoul.

"I don't have any advice for them on how to improve their performance. Instead, such growth will put Nissan in a difficult situation," Shiga said, according to Reuters.

"I wish the Koreans would slow down," he said to laughter from reporters. Shiga, also chairman of Japan's auto industry lobby group, was visiting Seoul to meet dealers and employees.

Over the past 10 years, Hyundai's global sales have more than doubled and its share in the key US market has soared to record highs. Hyundai and Kia now have a plant each in the southern states of Alabama and Georgia.

A Hyundai executive told Reuters on Thursday that the company expects to beat its 2011 global sales target as the European debt crisis and global economic uncertainty create an opportunity for it to pick up market share.

Japanese automakers should learn how to execute quickly like their South Korean rivals to avoid losing their competitive edge in the global market, Shiga said.

"Korean firms have improved their competitiveness sharply in terms of product performance, quality and design and personally, I admire their speed."