Whanganui District Council says it will create a new gang patch bylaw after its previous effort was deemed to be illegal.

Following lawyers' advice last week, councillors today voted to start the process required to make a new bylaw to ban gang insignia from being displayed in parts of the district and to seek central government legislation banning gang insignia, Mayor Annette Main said.

The new bylaw would address the issues raised in this month's High Court decision and the council hoped it would be in place by September, she said.

"There is clear support from councillors, the police and the Whanganui public that the gang insignia bylaw is a positive step forward in anti-gang legislation. It sends an important message to our community that we are committed to being a place that doesn't tolerate intimidation by gang members."

The Hells Angels gang sought a judicial review of the ban, arguing the 2009 bylaw - banning the wearing of gang insignia in public in Whanganui - was invalid.

Earlier this month Justice Denis Clifford ruled the bylaw did not specify to which public places the ban applied and was therefore invalid under national law.