New Zealand’s second terrorist attack in two years highlights weaknesses in existing counter-terrorism laws in preventing violent extremism. Beyond fast-tracking changes to terrorism suppression laws, there are still other areas of law and policy in New Zealand we need to urgently review.

Legislative change was already underway as part of an omnibus bill on terrorism. Following Friday’s attack, Prime Minister Jacinda Ardern will push parliament to pass those changes to terrorism suppression laws by no later than the end of this month, enabling stronger action against people who are considered a terrorist threat.

The perpetrator of Friday’s terrorist attack at an Auckland supermarket was under 24-hour surveillance and had recently been in prison for other terrorism-related offences. But as the judge noted, he could not be detained because the planning of a terror attack is not an offence under current laws.

The public has already made submissions on the new rules, and Ardern said a select committee is now considering changes that could prevent a similar attack.

While this will be very useful in the future, it is unclear how much value it would have had in yesterday’s attack.

Apart from the fact that law would have have had to exist before the attacker’s original convictions — it could not be retrospective — the elements of the crime (intent and ability to carry out the threat) would still have to be proven.

There are two other areas of law and policy that should be reviewed now. The possession or threat of violence with knives in public places is unlawful in New Zealand, but we may now need to consider rules around their sale and accessibility.

Another set of laws needing to be re-examined relate to how a Sri Lankan national who was a known high-level security risk managed to reside in New Zealand. As a principle, any non-citizen who represents a threat to national security should be deported.

This includes refugees. If compelling reasons of national security can be shown in a court of law with all appropriate safeguards, they too should be expelled. In exceptional circumstances, even if someone is a citizen of New Zealand but has citizenship elsewhere, and they act against the interests of the country, there are options to expel them.

This may be the biggest gap in our defences, this time. But when the review is done, we must have zero tolerance for extremists, of any flavour, who represent a serious threat to national security.

The attack was classified as an act of terrorism because it was done with the purpose of advancing an ideological, political, or religious cause that intended to cause terror in the country or force the government to change a position.

The fact it was ISIS-inspired is significant.

The world has watched the influence of ISIS in Afghanistan. It had taken seven years to defeat ISIS in Iraq and Syria, and at the height of that conflict, there were an estimated 30 to 40 extremists under watch in New Zealand.

Those figures were vague, and we can assume they were lower during the years ISIS lost influence and the war on terror faded from view. As ISIS efforts in the Middle East collapsed, New Zealand’s concern turned more to those attempting to return from the war zones.

The focus was primarily on New Zealand ISIS operatives overseas, but the influence in New Zealand was not invisible.

In 2016, a man was prosecuted for possession of objectionable material after he walked into the US embassy in Auckland, wearing an ISIS shirt, and asked if the embassy was “bomb proof”.

In another instance, a man with prior convictions for intimidating behaviour, threatening to kill, and assault with a weapon, was found guilty of possessing 62 items of objectionable material and making and distributing material from Islamic State, which the government had classified as a terrorist organisation. He was sentenced to three years and nine months in jail.

The laws around terrorism tend to evolve quickly after, not before, major attacks. For New Zealand, this meant our current foundation law, the Terrorism Suppression Act 2002 followed the attacks in the United States on September 11 2001.

This law has been amended multiple times over the following years, as the nature of the threat, and the need to better confront it, changed. Our most recent changes followed when terrorism hit New Zealand on March 15 2019.

The Christchurch mosque attacks were not fuelled by religious extremism but right-wing extremism. Other mass shootings around the same time period may have been narrowly avoided.

The government responded with a Royal Commission, legal change prohibiting firearms used in the attack and initiatives such as the Christchurch Call.

Agencies at the forefront of counter-terrorism reviewed their settings, splitting their counter-terrorism effort between violent extremism motivated by white identity and that motivated by religious faith.

As a result, New Zealand was better prepared for a terror attack. At the time of the Christchurch mosque attacks, the terrorism threat level was deemed low.

Yesterday, it was at medium, meaning an attack was “feasible and could well occur”. That proved to be right. New Zealand authorities were better prepared than last time, but gaps still allowed the attack to succeed. There is much more work to be done. Such incidents must not be allowed to repeat.