* Aug average per-day exports value falls for 2nd month
* Aug exports fall on year earlier for 10th straight month
* Figures underline doubts about pace of global recovery
* Manufacturing sector keeps expanding, survey shows (Updates with fresh data)
By Yoo Choonsik
SEOUL, Sept 1 (Reuters) - The value of South Korean exports per working day fell for a second consecutive month in August and shipments dropped at a double digit pace from a year earlier, underlining concerns that a global recovery will take time.
South Korea's exports are much stronger than at the start of the year during the height of the global economic crisis and South Korea's manufacturing sector is expanding, but recovery has sputtered in the third quarter as the world's biggest economies struggle to improve.
"The pace of recovery of South Korean exports has slowed in recent months after escaping fast from a deep trough, as China has appeared to scale down its stimulus on falling exports and the United States has yet to start its engines," said Jun Min-kyu, an economist at Korea Investment & Securities.
South Korea is the region's first major economy to report exports each month, so it provides early evidence on the state of global demand.
Exports per working day edged down to $1.26 billion in August from a revised $1.28 billion in July and $1.39 billion in June, the Ministry of Knowledge Economy said on Tuesday.
Although the figures suggest exports are losing some momentum, they remained well above the $0.98 billion in January when global demand had slumped. The per-day value is a widely used measure of changes between months, but the figures are not seasonally adjusted.
Reflecting the deep trough carved out by the global slump, the country's exports in August fell 20.6 percent from a year earlier, extending double-digit declines into a 10th consecutive month. The drop was slightly bigger than a 19.1 percent fall forecast in a Reuters poll.