Wanganui Mayor Michael Laws, says gang patches need to be banned in the city to stop what he describes as daily terrorism activity.
He has appeared before the Law and Order Select Committee, which is considering a local bill to outlaw gang colours and insignia in Wanganui.
Mr Laws says it will reduce intimidation and the recruitment of young people to gangs like the Mongrel Mob and Black Power.
He said information from the police shows gang offending has continued to rise since 2004.
While the legislation could breach the Bill of Rights, Mr Laws says that should be overlooked for the safety of the people of Wanganui.
He says two thirds of people in Wanganui supported banning gang insignia in the city in a recent referendum.