Kiwi spy agencies issued dozens of intelligence warrants before the Christchurch terror attack, but have refused to be drawn on their level of activity in the South.
A security analyst said he was surprised by the revelation the Security Intelligence Service (SIS) and Government Communications Security Bureau (GCSB) together issued 48 intelligence warrants between July 2017 and June 2018.
He said that level of activity indicated they were aware of a variety of threats, which could have included white supremacist terrorists.
Staff at both agencies would feel as though they had let New Zealand down by failing to detect the activities of suspected mosque shooter Brenton Harrison Tarrant, he said.
The latest annual report from the GCSB, which is charged with collecting and analysing intelligence information, said it issued 19 intelligence warrants in 2017-18.
Of those, 10 were type 1 warrants, for collecting information about New Zealanders.
The other nine were type 2 warrants, for "conducting intelligence collection'' against non-New Zealanders, he said.
The SIS, which is responsible for counter-terrorism, counter-intelligence and foreign intelligence, issued nine domestic intelligence warrants under previous legislation between July and September 2017, and two foreign intelligence warrants.
According to its annual report, the methods employed were "telecommunications interception, installation of interception devices including listening devices, and the taking and copying of documents and items''.
After new legislation came into force, 12 type 1 warrants and six type 2 warrants were issued between September 28, 2017 and June 30 last year.
Earlier this year, the Otago Daily Times submitted Official Information Act requests to both agencies, asking a variety of questions about their activities in Otago and Southland.
Information sought included the number of intelligence warrants obtained for activities in the South and the number of staff stationed in the region, if any.
Both agencies refused to confirm or deny they held the information requested.
They cited the section of the Act which allows agencies to withhold information which would be likely to prejudice the security, defence or international relations of the government.
A former intelligence consultant to US government security agencies, Paul Buchanan, said he was surprised by the number of intelligence warrants granted.
"I would have thought that in a country of this size maybe a dozen or so intelligence warrants would be needed per year.
"But maybe that indicates that there were a multiplicity of threats.
"Some of those may in fact have been white supremacists, but again too little too late.''
Dr Buchanan said a key question now was whether the agencies were too focused on detecting and preventing homegrown jihadists at the expense of violent right-wing extremists.
If Christchurch terror attack suspect Brenton Harrison Tarrant was not on the radar of intelligence analysts, then sweeping changes could be coming at both agencies, he said.
"If ... they were completely blindsided by these attacks, then there's bound to be, at a minimum, soul-searching and a complete review of operational procedures within both the SIS and the cyber side of the GCSB.
"There could be repercussions if someone dropped the ball and had information about this guy and decided it was not worthy of passing up the chain of command ... those people would probably face disciplinary sanction of some sort, because it's a dereliction of duty.''
Asked whether those in the intelligence community would feel guilty after the attacks, which left at least 50 people dead, Dr Buchanan said there was no question.
"From my experience with people in intelligence communities here and in the United States, I think all of them will feel guilty, all of them will feel like they let the country down.''
