A 2.1 percent monthly rise for all industries and a 2.9 percent jump in the mining and manufacturing sector in production for the month of June.
Statistics Korea says those were the biggest gains in more than three years and nearly five years, respectively.
But analysts say it's merely because of a base effect.
"June numbers look good because we saw a big drop in May. The indicators for investment and spending are not strong enough for us to see this as momentum for a faster economic recovery."
The rise in the mining and manufacturing sector is attributed to increased output in semiconductors and metal processing driven by demand from both home and abroad.
But investment in plants and equipment went down by 1.4 percent from May and spending also only edged up by zero.3 percent.
Although it was the first time the overall monthly output has risen since April's ferry disaster, experts say, it's too early to say that it signals the economy is emerging out of its sluggish spending trap.
They add it doesn't mean the Korean economy is not improving, but the rate it's picking up is still pretty slow.
Laah Hyun-kyung, Arirang News.