If the law was that urgent, you'd expect those powers to be used immediately. But it turns out they weren't. Yesterday the SIS released their first statutory report on the use of warrantless surveillance, and it speaks for itself:
The ability to issue a section 4ID authorisation came into effect on 12 December 2014.
During the period 12 – 31 December 2014, no authorisations were issued under section 4ID of the NZSIS Act.
So much for the case for urgency.
(See also: Peter Dunne's refusal to say how many times the new passport revocation powers, granted under urgency, have been used. That also speaks for itself. The urgency over the spy bill wasn't because the changes were urgently needed, but because the government wanted to limit debate).