Security agencies had no information to suggest the Australian man accused of the Christchurch mosque massacres should be placed on a watchlist or prevented from leaving the country.
Home Affairs secretary Michael Pezzullo, who is responsible for most of the country's security and intelligence edifice, said the accused gunman had spent just 45 days in Australia during the past few years.
"There was no reason to restrict his movement because nothing had come to attention ... to suggest that he was on a pathway to violence," Mr Pezzullo told a budget estimates hearing in Canberra on Thursday.
"There was nothing in any of our systems that would have suggested that either this person's travel be restricted, or that he otherwise be the subject of laws enforcement attention, up to and including arrest."
Australian man Brenton Tarrant has so far been charged with one count of murder and will appear in a New Zealand court on Friday.
He had travelled extensively since 2010 before settling in the New Zealand city of Dunedin.
Some 50 people died and dozens more were injured after a gunman opened fire in two mosques in Christchurch last month.
