He said it was difficult to rebut criticism with the traditional "neither confirm or deny" response previously used by officials and politicians. "Our recent experience is that hasn't helped.
"Over the last while the community has realised it needs to offer more of a foundation in public of the communities' work. That means questioning just how much of what we do need to stay behind the veil.
"There are real risks in unthinkingly disclosing certain material that could have an impact on security. We will get better at making judgments around that. Hopefully we won't make any mistakes as we do."
He said the transition for some of those in the agencies was "difficult", having operated in a cone of complete silence for decades. It would see information released which gave insights into the way the agencies worked, he said. "That's going to be pretty challenging but in the end will be more fulfilling for them."
The increasing openness comes at a time DPMC is shifting the way "national security" is handled, extending responsibility beyond the intelligence agencies traditionally tasked with keeping New Zealand safe to include a wide range of public bodies.
It has meant the government has taken a "national security" response to man-made and natural disasters including the two Christchurch earthquakes and Pike River along with more traditional perceived threats. The focus has also shifted from having systems to meet known threats to broadening the safety net to anticipate threat and achieve the specific outcome of a safer nation.
It was led by "pretty thoughtful people doing a very hard job doing their best to improve the citizen's experience".
Asked to compare the intelligence agency staff to the police, where he worked for 35 years, he said: "They're the same sort of people - good New Zealanders who have chosen to embark on their public service through these organisations. They have the same sense of commitment. They have a professional pride."
Information released in the six months included the GCSB's recent decision to meet a Herald request for copies of its previously secret Signals Intelligence Directive, known as NZSID7, which governs its rules for using powerful electronic spying equipment.
Mobile and App users read Nationality Policy document here
It makes New Zealand the second of the Five Eyes nations to make the information available to its citizens, following the United States' declassification of its version of the document "US SID18". The release of the US document followed Barack Obama's instruction to the NSA to release details of its electronic eavesdropping safeguards a year ago in response to Edward Snowden's NSA leaks.
The US document is acknowledged in the GCSB material while comparative guidelines for Australia, Canada and the United Kingdom remain secret.
The uncharacteristic outpouring of previously secret information included SIS material from the Kim Dotcom affair which had apparently been overlooked in the previous 30 months of the case.
The States Services Commission made available the long-guarded Murdoch Report on the intelligence community, which described NZ's contribution to the Five Eyes partnership as "niche" but one which earned it access to greater capabilities.
And John Key - who was until recently minister for the agencies - made public details about a nationwide cyber-protection plan called Cortex although in the context of rebutting claims of mass surveillance made during the election period.
Since the illegal spying on Dotcom was exposed, the intelligence community has established a communications team of two people.
The team produced a "communications plan" for the NZ Intelligence Community , released to the Herald through the Official Information Act, which listed objectives such as having the public value the agencies' contribution and having media feel it was approachable. It also aimed to "address reputational damage".
Mobile and App users read Draft Communications Year One Plan here
Mr Broad's comments follow a recent State Services Commission report into the intelligence agencies which said they faced formal and public review next year and needed to show "their value to New Zealand to a much greater degree than possible now, and that they can be trusted".
Mobile and App users read 05/11/2014 OIA Request David Fisher Response here
