The Act Party wants to prevent certain gang members from "bad behaviour" and instead require good behaviour in a proposal that could violate the principle of "innocent until proven guilty".
It's part of a raft of law and order proposals the party has released today, including a check on gang members' benefits to prevent them from gambling, or buying alcohol or tobacco.
Act also wants policing numbers to increase in line with population growth.
"We are announcing a raft of policies to make New Zealanders safer in their communities," Act leader David Seymour said.
"We would introduce gang injunction orders, take the politics out of policing, put gang members who receive welfare on electronically monitored spending, and get rid of the target to reduce the prison population."
The centrepiece of today's announcement is a Gang Injunction Order, granted by a court following a police application against an individual on the National Gang List.
Police would need to have a reasonable belief that the individual posed a particular risk of committing gang-related violence or drug-dealing offending.
"The injunction order could then be used to prohibit bad behaviours including being in a particular location or associating with particular people," Act's justice spokeswoman Nicole McKee said.
"It could also be used to require positive actions, like attending rehabilitation."
Seymour said that the presumption of innocence could be stripped if it was reasonable to do so.
A 2017 review of the use of such injunctions in Merseyside, the UK, found individual offending dropped by 70 per cent in the three years after their gang injunctions.
"Comparisons between gangs with injunctions and gangs without showed downward crime trends in the injunction gangs that were not observed in the comparisons during the same time periods, but regression to the mean could not be ruled out as an explanation for the findings," the review said.
Injunctions have also been used in Los Angeles, but have been criticised as being used by LA police to profile communities of colour. Their use across blanket areas of the city has been successfully challenged in the courts as unconstitutional, and they must instead be used against individuals.
To counter gun violence, the Government has proposed Firearms Prohibition Orders to keep high-risk people - not just gangs - from accessing, being around, or using firearms.
A person would need to specifically commit a crime, go through a court process, and qualify under the FPO conditions.
The Government partially blames the deportation of 501s from Australia for the rise in gang member numbers, which have ballooned by 50 per cent since Labour took office and currently number about 8000.
Seymour also wanted the number of per-capita constabulary officers - currently at 200 for every 100,000 New Zealanders - to be maintained, and to abolish the Government's target to reduce the prison population by 30 per cent by 2032.