Banning gang patches will make gangs more difficult to police and the streets more dangerous, says a former head of Auckland police's specialist motorcycle gang unit.

Cam Stokes, who left the job in 2003, said banning patches would only make it easier for gang members to break the law undetected and may also put the public at greater risk.

"Patches make it easier for police and the public to identify them. If members of the public can see they are gang members then they have the option of staying away from them," Mr Stokes said.

Wanganui City Council has proposed a bylaw which would ban gang patches and colours in the city's public places, following a history of problems. Eleven people were arrested in the city this month in relation to violent clashes between Hell's Angels and Mongrel Mob members.

"I fully understand their [Wanganui's] situation and I support what they are trying to do in terms of getting tough on gangs. I just don't think it is the right way to go about doing it," said Mr Stokes - a drug education consultant.

"You need to address the offending. With gangs, you address the gang members, not the clothes that they wear."

Mr Stokes, who spent most of his 18 years in police service as a gang specialist, said making sustainable progress in policing gangs required a committed and systematic approach from the police, which he said was currently absent.

When he left the police he was a detective sergeant in charge of the Auckland motorcycle gang unit which at five members contained more than half of the country's gang specialists.

Specialist gang units have since been subsumed into organised crime units which, Mr Stokes said, are too busy to properly police gangs.

Organised crime units did big operations and might do only one or two checks a year, which in a town with several gangs means a gang might not be scrutinised for several years.

"What is also needed is the day-to- day pressure on [gang members], getting informants, disrupting their lives and making things more difficult for them."

The police approach to gangs now lacked a national focus. While a few areas were doing "great work" the police can do better.

"We are not sharing our knowledge pool as well as we might and we are not looking after our gang experts at the same time.

"At the moment we have got one part-time detective sergeant and a couple of analysts."

Mr Stokes said a lot of "good gang cops" had walked out the door.

It was a challenging area of policing and one not supported by guidelines, standards or career path. Those who became specialists did so on their own and few stayed long-term. There were no rewards, other than personal satisfaction, Mr Stokes said.

His prescription for improving policing of gangs was an adequately resourced dedicated national gang unit which included an advisory panel of experts.

The unit could be dispatched to help local police with significant gang events and advise the Government on such things as law changes.

Better laws was the "other big thing", Mr Stokes said.

"For example our problems include gang violence. So let's bring in laws that target that. Let's make it an offence for gang members to be in possession of weapons and make it a mandatory jail sentence so the message gets passed that if you are a gang member and you choose to carry weapons you are going to jail."

Currently a gang member found with a folding knife would get off a charge of carrying a weapon in a public place without a reasonable excuse by claiming it was for cutting apples.

The Police Association has lent support to Wanganui banning patches but wanted the proposed bylaw to be part of a "co-ordinated approach" involving central Government and senior police, who association president Greg O'Connor said had failed to acknowledge the extent of the gang problem.

Wanganui Mayor Michael Laws has said a bylaw would allow people to feel safer on the streets and "removes the strut factor of the gangs and their intimidation of the people of Wanganui".