A North Korean navy truck carries the 'Pukkuksong' submarine-launched ballistic missile during a military parade in Pyongyang, this month.

Newly released documents sourced from NSA whistleblower Edward Snowden reveal details of the intelligence community's planning for large-scale evacuations and the response to a North Korea attack.

The Intercept news website - run by Glenn Greenwald and a team of investigative journalists - released a batch of 251 internal National Security Agency newsletters, a publication called SIDtoday.

The document dump includes references to the global intelligence community's network of member spy agencies, which includes New Zealand's intelligence agency.

REUTERS Edward Snowden was responsible for the National Security Agency leaks in 2013.

In 2004, the newsletter says, there were "critical gaps" in the second-party intelligence sharing capabilities of the main spy agencies in New Zealand, the US, the UK, Australia, and Canada with their counterparts in South Korea.

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The batch of documents from the Snowden archive covers the second half of 2004 and details agency difficulties with Arabic language material, work with other agencies, the relationship with Japan's spy agency, and material about domestic operations.

It also includes a "Korea Issue Management" team newsletter about the "6th Rock Drill" - which appears to be a desktop drill on intelligence and counteroffensive readiness in the event of a North Korea attack, mass evacuations, and the management of a unified Korea.

Information sharing capabilities among members of the spy alliance were of concern, the top secret newsletter says.

"For the first time, the [Korea team] addressed the SIGINT [signals intelligence] response to Non-combatant Evacuation Operations (NEOs) in both Seoul and Pyongyang, eliciting a great deal of discussion from both First and Second Party attendees.

DAMIR SAGOLJ/REUTERS North Korean leader Kim Jong Un waves to people attending a military parade.

"The next scenario addressed tactical SIGINT in a counteroffensive responding to a North Korean attack and the final brainstorming session concerned...operations in a newly-unified Korea.

"In all of these conversations, the partners provided a unique perspective that energised the exchange and highlighted critical gaps.

"Most important among these gaps was communications between and among the US, Great Britain, Australia, Canada and New Zealand. Almost all of these difficulties are a direct result of our agreements, policies and practices associated with the combined US-South Korean...SIGINT partnership and, therefore, require creative thinking and/or policy changes to resolve."

Investigative journalist Glenn Greenwald.

The newsletter said there was an issue with the "threat warning networks" and most, if not all, computer networks could only be accessed by the US and South Korea.

The Intercept said the rehearsal depicted scenarios involving civilian evacuations from Seoul and the North Korean capital Pyongyang during a hypothetical attack.

"In the discussions, 'critical gaps' were found in communications with trusted Five Eyes countries, which did not have access to the computer networks for the 'Korea Theatre of operation"'.

SIDtoday is the agency's internal newsletter covering the NSA signals intelligence directorate and the work of its spies and partners in the "Five Eyes" alliance, which includes New Zealand, Australia, Canada, the United Kingdom, and the United States.

Five Eyes alliance members were in New Zealand this week for a meeting.

FBI director James Comey​ was in the country and the director of the CIA, Mike Pompeo​, was also believed to be among the delegates.