"The intelligence reporting GCSB receives from its international Signals intelligence partners is what those agencies collect themselves based on their own priorities."
These partners had their own legal mandates, which might also influence what intelligence they collected, Hampton said.
He did not respond to RNZ's question of whether the gap in reporting from overseas on the far-right was continuing. He replied that intelligence reporting was "highly classified and we are unable to provide further details on this".
However, he added: "GCSB shares our intelligence and security priorities with its partners and, since the 15 March, 2019 attacks, has emphasised to them the importance to New Zealand of countering white identity extremism."
The reporting gap existed despite far-right terror attacks in the West among partners countries rising about threefold in five years by some counts, and even though one partner is the US, where the threat from white supremacists had been acknowledged as ramping up since the 2017 Charlottesville car attack.
Yet the US has had many of its own problems with lack of focus on domestic terrorism, and led the world in its fixation on Islamic terrorism.
"While international partners do not direct or dictate that New Zealand agencies pursue particular leads or ideologies, partner reporting and partner-supplied leads necessarily informed the development of New Zealand threat assessments and affected the allocation of resources, certainly by the counter-terrorism agencies," the commission's 800-page report said.
The Royal Commission is revealing, too, about other weaknesses at the GCSB.
It had just single-figure numbers of staff dedicated to counter-terrorism in the four years before the attacks - as low as two, as high as seven, out of almost 500 employees.
Its "mission-critical" internet operations were last year gauged by Treasury as five years behind the Five Eyes partners, the inquiry said.
The bureau gave the Royal Commission the message that it thought counterterrorism was better handled by other agencies.
However, the commission gave the GCSB a largely free pass.
"It engages in domestic counter-terrorism activity only when tasked by another agency."
It concluded the bureau was reliant for direction from the police or the Security Intelligence Service - SIS - and they weren't giving much.
This was partly because those two agencies themselves were not well versed in the GCSB's unique information - collecting powers.
The SIS "possibly correctly, does not regard it as appropriate or necessary for its staff to have a full understanding" of the GCSB's capability.
But without that understanding, the SIS's "ability to maximise contributions from signals intelligence to the counter-terrorism effort is constrained", it said.
It added the GCSB's relationship with police "is not particularly close".
This model, a "customer-led" one, and its shortcomings had not been discussed.
"Its customers did not always have sufficient understanding of signals intelligence capabilities to know how its contributions could be maximised."
The government has focused on the commission's finding that no public agency failed to meet required standards in counter-terrorism efforts before the attacks.
However, this is preceded by another finding - for a "systemic failure of the counter-terrorism effort" across six areas, most notably the police, SIS and the Department of Prime Minister and Cabinet (DPMC), which was meant to provide oversight but often did not.
One of the six flaws was "the reality that the system did not force or at least encourage public sector agencies to discuss their individual strategies and any residual risk they were carrying and thus identify gaps in the system".
The horizon scanning in the DPMC was inadequate and did not properly consider the radicalising role of the internet.
The GCSB had, by 2019, had five years to improve its internet operations but was struggling, even though "the capability was fundamental to the mission of the entire New Zealand intelligence community".
The bureau, it said, should pitch in more, as it "has the potential to make a key contribution to the counter-terrorism effort because it can collect information that no other public sector agency can collect."