North Korea on Wednesday rejected a UN Security Council statement condemning the reclusive state for its latest missile tests and threatening to take "further significant measures".

"The DPRK categorically rejects this as an intolerable act of encroaching upon its dignity, right to existence, sovereignty and right to self-defence," a spokesman for the Foreign Ministry of North Korea was quoted by the official Korean Central News Agency (KCNA) as saying.

The statement by officials in Pyongyang follows the test-firing by North Korea of three ballistic missiles on Monday, as world powers gathered for a G20 meeting in China, with leader Kim Jong-Un hailing the tests as "perfect".

In a meeting to consider a response to the tests, the 15-member Council said the launches were "in grave violation" of North Korea's international obligations and UN Security Council resolutions, warning it would closely monitor the situation.

The document was adopted unanimously, including by Pyongyang's only ally China.

UN resolutions bar North Korea from any use of ballistic missile technology, but Pyongyang has nevertheless conducted a fourth nuclear test and a series of missile tests this year, prompting South Korea to announce plans to deploy a US anti-missile system to counter such threats.

The isolated communist state has been hit by five sets of UN sanctions since it first tested a nuclear device in 2006.

KCNA reported that Kim personally oversaw Monday's missile firing, and vowed that the isolated state would continue to build its nuclear arsenal.

The North will continue to bolster "the nuclear force in a phased way in this historic year", the spokesman said.

US President Barack Obama held talks on Tuesday with his South Korean counterpart Park Geun-hye on the sidelines of a regional summit in Laos.

Obama said after the meeting in Vientiane that North Korea needed to know that "provocations will only invite more pressure and further deepen its isolation".

Last month, North Korea fired a submarine-launched ballistic missile from the northeastern port of Sinpo that far exceeded the range of the country's previous sub-launched missiles.

Kim described the August test as the "greatest success" and said it put the US mainland within striking range.

The launch was widely condemned by the US and other major powers, but analysts saw it as a clear step forward for North Korea's nuclear strike ambitions.

burs-eb/sg