Enacted following the September 11 attacks in the United States, the Act was designed to better address contemporary terrorism issues, both domestically and abroad.

Prior to 2001, incidents included the bombings of a rail bridge near Huntly in 1951, the Wanganui Computer Centre in 1982, the Wellington Trades Hall in 1984 and the Greenpeace vessel The Rainbow Warrior in 1985.

[6] Due to these incidents, New Zealand had already established prior to this act, "A comprehensive legislative and substantive counter-terrorist framework..."[7] However the growth of international terrorism in recent years, alluded to by then Minister of Foreign Affairs and Trade Phil Goff in the bill's first reading, gave rise to the need to introduce new, "comprehensive" anti-terror legislation.

[10] Seen by many as simply the enactment of two recent international conventions, the bill was considered unremarkable and garnered widespread lukewarm support.

For instance in its submission on the bill the Women's International League for Peace and Freedom (Aotearoa), an organisation with consultative status with the United Nations, claimed to be, "dismayed at the extremely short length of time" and did not, "consider such a time period to be sufficient for...such a complex, and extreme, piece of legislation.

Greener-Barcham claims that this was in order, "To be part of a broader anti-terrorist effort" and to, "Strengthen ties with 'like-minded states'" following the September 11 attacks and President Bush's call to arms.

[22] In October 2007, the NZ Police carried out several raids across New Zealand and arrested 17 individuals, charging them under the Terror Suppression Act for involvement in so-called "military style training camps.

There is insufficient evidence to establish to the very high standard required that a group or entity was planning or preparing to commit a terrorist act, as that term is defined in the legislation.

The amendment was to correct inconsistencies with UN and UN Security Council requirements and replace the role of the High Court in extending terrorist designations with the prime minister.

Green Party co-leader Russel Norman claims this is because the government "is unwilling to risk further public scrutiny of the state's search and surveillance powers.