Police hope an increased focus on gang activity will pay dividends.
The gang patch ban has been in force since midnight.
Police Assistant Commissioner Paul Basham says in the lead up to the ban, there was an increase in reports of gang members wearing their patches prominently in public.
He says they get reports on criminal behaviour all the time, so this increase was that combined with a heightened awareness from the public.
Basham told Ryan Bridge the legislation will create opportunities to catch other crimes.
He says targeting small groups with high offending rates has a disproportionate effect on crime.
LISTEN ABOVE

Kevin Putt: Former Springbok previews the final Greatest Rivalry test between the All Blacks and Springboks
02:18

Leon Panetta: Former Defence Secretary and CIA Director on the US-Iran war
08:17

Graeme Edgeler: Constitutional law expert on an MSD review which found more than 30-thousand cases, where benefits and payments were wrongly suspended
04:04