* Hyundai global sales reach 371,743 vehicles, up 3.4 pct
* Strike ends, but domestic sales remain weak
* Hyundai may have benefited from anti-Japan protests in China
By Hyunjoo Jin
SEOUL, Oct 4 (Reuters) - South Korea's Hyundai Motor Co said global sales returned to growth, rising 3.4 percent in September from a year earlier, after strikes at domestic plants ended and as it benefited from boosts to U.S. and China production.
The figures, although below some expectations for record monthly numbers, will provide some reassurance that Hyundai has put its costliest strike ever behind it. Analysts worry, however, about the impact on third-quarter earnings which are due late this month.
"September results fell short of expectations because domestic sales remained sluggish despite the end of strikes and the start of discount programmes," Suh Sung-moon, an analyst at Korea Investment & Securities.
Hyundai said worldwide sales rose to 371,743 vehicles last month, the highest level since June. But sales for affiliate Kia Motors Corp were almost flat as strikes there ran until Sept. 11 while Hyundai's strikes were over in August.
Hyundai's sales in August had fallen 4.6 percent, the automaker's first monthly sales decline in more than three years, hit by the partial walkouts due to wage disputes. The South Korean plants supply about half of Hyundai's vehicles sold globally and prevented it from making 82,088 cars worth some $1.5 billion.
Hyundai shares ended down 0.8 percent prior to the sales figures, while Kia stocks were up 0.3 percent.
Hyundai did not give a regional breakdown, but analysts said it likely posted solid China sales at a time when its Japanese rivals are struggling in the wake of a territorial row that has provoked anti-Japan protests in the world's biggest auto market.
Mazda Motor Corp, the first of Japan's automakers to report China sales for September, said on Thursday that sales plunged 35 percent from a year earlier.
Hyundai's new factory in China, which makes its popular Elantra compact car and started production in June, has allowed it to increase supply. In contrast some Japanese rivals are cutting back output there.
"Hyundai has more cars to sell now in China, and this helps Hyundai accelerate sales and woo customers from struggling Japanese carmakers," said Suh.
But Goldman Sachs has said the benefit for non-Japanese brands is likely to be small, although Japanese vehicle sales in China are expected to fall 7.4 percent this year as a result of the protests.
The automaker also added a third shift to a U.S. plant, which also makes the Elantra, from September, providing a timely boost to production.
U.S. sales figures showed Hyundai's sales in September jumped 15 percent from a year earlier, outperforming a 13 percent climb for the industry overall.
But even with the recent production boosts, analysts fret that Hyundai is not making the most of its opportunities and that production capacity is being stretched globally.
Hyundai's U.S. share market has failed to show major gains, at 5 percent in September compared with 4.9 percent a year earlier, while Japanese rivals like Toyota Motor Corp have now made a strong comeback from the post-earthquake problems that bedevilled them last year.
Hyundai would argue, however, that its cautious approach to increasing capacity is paying off. Led by Chairman Chung Mong-koo, the automaker has slowed capacity addition in the past couple of years to focus on quality and branding.
Its brand value jumped 24 percent to the seventh place among automakers, outpacing Audi, according to brand consultancy Interbrand's 2012 Best 100 Global Brands released this week.
In Europe, Hyundai is an outperformer but the automaker is expected to fail to meet its Europe sales target this year, hurt by the region's debt crisis. Its September sales for the European Union will be released later this month.