The disruption came amid an escalating war of words between the United States and North Korea over a massive cyberattack on Sony Pictures.
Though there has been no comment from the authorities in Pyongyang, US experts reported the restoration.
Some analysts say the country’s web access was cut entirely for a time.
Washington said that it would launch a proportional response to a cyber-attack on Sony Pictures, which made a comedy about North Korean leader, Kim Jong-un but U.S. officials said Washington was not involved.
Officials would not comment on any US involvement in the current outages.
CEO of U.S.-based CloudFlare which protects websites from web-based attacks, Matthew Prince, said the fact that North Korea’s Internet was back up “is pretty good evidence that the outage wasn’t caused by a state-sponsored attack, otherwise it’d likely still be down for the count”.
Almost all of North Korea’s Internet links and traffic pass through China and it dismissed any suggestion that it was involved as “irresponsible”.
U.S. President, Barack Obama, told CNN on Sunday that the hack was “an act of cyber vandalism that was very costly, very expensive” but that he didn’t consider it an act of war.
He had previously said that the United States would “respond proportionally” to the attack on Sony, without giving specifics.
The outage brought down sites run by the Korean Central News Agency and the Rodong Sinmun — major mouthpieces for the regime — according to the South Korean news agency, Yonhap.
Meanwhile, South Korea, which remains technically at war with the North, said it could not rule out the involvement of its isolated neighbour in a cyberattack on its nuclear power plant operator. It said that only non-critical data was stolen and operations were not at risk, but had asked for U.S. help in investigating.
China’s permanent representative to the United Nations has called for all sides to avoid an escalation of tension on the Korean Peninsula after the UN security council put the North’s human rights record on its agenda.
The United States asked China to identify any North Korean hackers operating in China and, if found, send them back to North Korea. It wants China to send a strong message to Pyongyang that such acts would not be tolerated, the officials said.
The Chinese Foreign Ministry said on Monday it opposed all forms of cyberattacks but there was no proof that North Korea was responsible for the Sony hacking.
North Korea has denied it was behind the cyberattack on Sony and has vowed to hit back against any U.S. retaliation, threatening the White House and the Pentagon.
The hackers said they were incensed by a Sony comedy about a fictional assassination of North Korean leader, Kim Jong Un, which the movie studio has now pulled from general release.
China is North Korea’s only major ally and would be central to any U.S. efforts to crack down on the isolated state. But the United States has also accused China of cyber spying in the past and a U.S. official has said that the attack on Sony could have used Chinese servers to mask its origin.