The National Party is accusing the Government of virtually ignoring gangs and then trying to appear tough in the run-up to the election.
Corrections Minister Phil Goff is considering a ban on gangs, which would prevent members from associating with each other.
Mr Goff is assessing the effectiveness of a crackdown to outlaw gangs in South Australia.
Under that law, gang members can be banned from talking to each other and from certain places and events.
It allows gangs to be declared criminal organisations, and control orders to be issued stopping members from communicating with each other.
Breaches of the law are punishable by up to five years in jail.
Mr Goff says he is seriously evaluating the law to decide whether it would work in New Zealand.
However, National Party justice spokesperson Simon Power says it is a desperate and cynical effort by a government behind in the polls.
Mr Power says Justice Minister Annette King recommended to Cabinet in March this year that there be no further changes to the law and told Parliament a ban on gangs would not be feasible.
He says National will also keep a close watch on the effects of the South Australian law.
Its own gangs policy, outlined last year, includes strengthening the law that makes it illegal to be a member of a criminal gang and giving police more powers of surveillance.
Wanganui Mayor Michael Laws, whose council has its own bill before Parliament to ban gang patches, has welcomed news that the Government is considering outlawing gangs.
Mr Laws says it is a welcome and significant shift in government thinking.
Mr Laws says gangs exist only for criminal purposes, but at present there is no daily pressure on members and their activities.
Police Association president Greg O'Connor agrees such a law would turn up the pressure on gangs.
Mr O'Connor says New Zealand is also lagging behind Australia in asset seizure legislation, which would help police fight criminal gangs.