Peter Dunne says the breach of his privacy by the Henry inquiry probing the leak of a report into the GCSB was down to its "shoddy" approach.
United Future Leader Dunne resigned after refusing to release the full content of his emails to Fairfax reporter Andrea Vance to inquiry head David Henry.
Mr Henry's report found Mr Dunne exchanged a series of emails with Ms Vance in the days before her article revealing key points of the GCSB report including potentially illegal spying on New Zealanders by the agency.
Flanked by leading constitutional lawyer Matthew Palmer, Mr Dunne told Parliament's privileges committee this morning that unlike other ministers, he had never received requests from the Henry inquiry or anyone else for his permission for the release of records about his phone calls and emails.
"My email metadata and mobile phone records were accessed without my approval, my swipe card details were provided for a period longer than that to which I had agreed, and, while my landline records were accessed with my approval, I do not know for what period of time, or whether records of my calls, other than those to Ms Vance were handed over."
He said the protocols governing access to ministers' electronic data were at best unclear and at worst non-existent.
"In this instance what existing protocols there were, were clearly unknown to most of the agencies involved, and applied in a very haphazard way."
Asked by Green MP Kennedy Graham whether he believed his permission for the release of is his information was not sought because of his status as minister outside Cabinet, Mr Dunne said it was: "probably more a case of oversight to be frank".
The inconsistency of his treatment compared with other ministers was "symptomatic of a pretty shoddy haphazard approach" by the inquiry.
Earlier this morning, Parliament's Clerk of the House Mary Harris told the committee she and her staff weren't involved in the release of information to the inquiry and she believed Parliament had been let down by the incident.
She said there needed to be clarity around the rules for releasing any information to future inquiries and told the committee she hoped it would be able to provide that clarity.