The tests are being seen by some analysts as an attempt to gain the upper hand ahead of an expected resumption of talks on ending the North's nuclear weapons programme, rather than a direct security threat.
"Bilateral, and possibly multilateral, talks with North Korea are coming up soon, and North Korea is playing all its cards before they happen," Koh Yu-hwan, an expert on the North's negotiating tactics at Dongguk University in Seoul, said.
The latest missile tests are the first in about three months and follow an apparent thaw in relations on the Korean peninsula.
Nonetheless, the tests seem unlikely to halt growing momentum for dialogue after Pyongyang told visiting Chinese premier, Wen Jiabao, last week that it was ready to resume the stalled disarmament talks.
South Korea's foreign ministry said Monday's launch of the five surface-to-surface missiles with a range of up to 120km, breached UN resolutions and urged its neighbour "to abide by the UN Security Council resolutions".
But officials in Seoul generally played down the launches, saying they were often part of routine military drills.
|Seoul says talks on reunions for Korean families are likely to proceed [Reuters]
"The missiles are identical to the ones that had been fired numerous times in the past, so we don't believe there will be problems on holding talks, which will go ahead," Chun Hae-sung, a spokesman for South Korea's unification ministry, said.
And Hillary Clinton, the US secretary of state, said on Monday that Washington's efforts "to work toward a nuclear free Korean peninsula … is unaffected by the behaviour of North Korea".
The US is considering the North's precondition that Washington and Pyongyang hold bilateral talks before any multilateral talks can resume.
North Korean state media has so far made no comment about the missile launches, which in the past have often been accompanied by belligerent rhetoric usually targeting the US and South Korea.
Regional financial markets brushed off the North's latest moves and financial analysts do not expect a major impact in the absence of direct military conflict.
The latest raft of missile tests also come as the North agreed to hold fresh talks with the South on flood control measures and family reunions.
On Tuesday, Pyongyang accepted a proposal by the South for working-levels talks on preventing flooding in a major river that flows across the neighbours' armed border, where a surge of water released from a dam by the North killed six people in the South last month.
The North also agreed to hold another round of talks on arranging reunions for families separated by the 1950-1953 Korean war, a move that could help warm ties between the two sides.
Officials at South Korea's unification ministry said those talks would probably take place later this week.