Under the proposal, National wants to prevent gang members from hanging out with other gang members.
It also proposes setting up a specialised police unit in New Zealand to check for liquor licences if alcohol is served at a gang pad, inspect tax records for welfare fraud, take away drivers' licences if traffic fines are unpaid, and use council rules to shut down gang clubhouses for shoddy workmanship or unconsented work.
National also wants a ban on gang patches from public places, revoke parole for gang members who return to gangs on release, create new sentences for violent gang crime and have greater police powers to search the homes and cars of gang members.
"As long as they deal and manufacture drugs and carry out violence in our communities I will do everything I can to stop them," Mitchell told the Rotorua Daily Post.
"As for receiving the dole, our policy is that gang members should prove they're not receiving illegal income. If gangs are following the law then they have nothing to worry about. If they're breaking the law, they don't deserve taxpayers' money."
His comments come after Mongrel Mob's Ōpōtiki chapter president Barney Hunuhunu said National's policies were concerning and would split up families.
Hunuhunu has led the chapter since 2008.
"The bottom line is he wants to get rid of gangs themselves, which would take longer than his lifetime. Good luck to him," Hunuhunu said.
He said in many cases multiple members of the same family were part of the same chapter or wider gang.
"A gang member today is often a son, a moko - they're whānau of others in our crew. Are we not allowed to spend time with our own family members? Our friends have married into our families."
Hunuhunu said National's proposals to stop gang members' social welfare support would ultimately hurt families supported by gang members.
Whanau Ora commissioning chairwoman and Rotorua district councillor Merepeka Raukawa-Tait has also condemned National's new gang plans, calling them "a big fat waste of time".
"I don't see anything changing with what they are proposing. Obviously, no one has sat down and thought through 'what are we really trying to achieve here?'"
Like Hunuhunu, she said gangs were whānau.
"They operate within their own ecosystem for their own survival. They know no one gives a **** about them, and being marginalised they survive by any means possible. And they have.
"Simon Bridges had the same opportunity as I had recently to speak at the Waikato Mongrel Mob Kingdom Chapter. Why didn't he go and tell them he was coming after them?"
Raukawa-Tait said aging gang leaders wanted their mokopuna "to have better opportunities than they had".
"They are acutely aware that methamphetamine is stunting their younger members in particular, in all areas of their lives ... With National running the line 'hit them and hit them hard' I only see seriously injured police officers or worse. The gangs have nothing to lose by fighting back."
She said "new thinking" was needed.
"That will involve talking to some of the gang members who have managed to turn their lives around. What brought about their desire to change, who influenced this change and how have they managed to stay out of trouble?
"No one says it will be easy but National are taking a back to the future approach. Never worked then, won't work now."
However, Rotorua father Rendall Jack, who believes a Rotorua gang was behind his son's murder, has called National's policies "a move in the right direction".
"It worries me that people who haven't been affected or had their life changed by gangs will struggle to recognise the danger or threat they pose. Most gang crime is not reported because they use fear tactics, threats and, when the opportunity arises, they extort.
"It is the usually drug-fuelled bravado image and their training that desensitises them to the carnage they cause and the people they hurt."
He said banning patches would make gangs far less appealing to recruits.
"Instead of intimidating others, they become the target and the bane of the public eye. A strong and equipped force directed at them would change the game. People will feel safer when gangs are put in their place."
Figures released by Police Minister Stuart Nash earlier this year showed one in five of New Zealand's patched gang members lives in the Bay of Plenty.
The total number of patched gang members in the country had increased by 26 per cent since October 2017.
Bay gang member numbers rose from 1058 in 2017, to 1380 to the end of August this year.
National's proposals raise human rights issues including freedom of movement, freedom of association, freedom of expression, the presumption of innocence and the right to be free from unreasonable search, an expert said.
Waikato University psychology and crime senior lecturer Dr Armon Tamatea told the Rotorua Daily Post National's focus on gangs failed to consider the large numbers of offenders who were not gang-connected.
"The approach is clearly militant."
He said he was "no apologist to gangs" but felt National's policy would promote marginality, "which is often a large reason why people join gangs in the first place".
"I think cosmetically this approach will appeal to people who have black and white views of gangs but this can also create more problems, such as gangs going underground."
He said National's policy would not help address related issues such as poverty, racial marginalisation, health inequities, and suicide.
Prime Minister Jacinda Ardern shunned National's plans.
"Our police already do incredible work... We already have organised crime units, we have specialists within New Zealand police on the issue of gangs."
She said of the 1800 new police officers this parliamentary term, 700 were tasked with tackling organised crime and gangs.