Police swarmed on Hells Angels bikies this afternoon, arresting one, as the group of 50 gang members rode toward Wellington on their way to the South Island.
About 80 police officers turned out to stop the gang members at Plimmerton, north of Wellington, as they travelled to catch a ferry across Cook Strait this afternoon.
Police stopped the entire group at the Plimmerton roundabout, requiring them to undertake roadside breath tests, and checking their license and vehicle details.
Police said their staff included response, road policing, investigations and specialist staff to ensure the gang members were sober, licensed to drive and had roadworthy vehicles.
One of the group was arrested for possession of an offensive weapon - a knuckle-duster - but the rest of the gang was co-operative.
"These operations are always a balancing act. We want to quickly and efficiently check that the group is lawfully on the road while causing minimum disruption to other motorists using State Highway 1 at this time," Inspector John Spence said.
It is understood members of the motorcycle gang boarded a 1.30pm ferry to cross the Cook Strait.
The Hells Angels Nomads support crew vehicle was seen cruising through Wellington's ferry terminal shortly before 2pm.
The chapter is a splinter group from the outlaw motorcycle gang who wear an 81 on their patch.
They are separate from the original New Zealand Nomads chapter - initially a faction of Black Power - which split from the fraternity in the 1970s and wear a 77 on their insignia.
It is understood the Hells Angels were travelling for a meeting being held in Nelson from tonight until Sunday.
Earlier this week Nelson police declined to speculate on whether the gang's trip was a prospecting or initiation event.
Nelson police would not at that stage reveal their plans for monitoring the influx, but confirmed there would be a police presence for the duration of the gang's stay.
In May, Canterbury University sociologist and gang researcher Jarrod Gilbert said the Hells Angels appeared to be annexing another outlaw motorcycle gang.
The Red Devils were said to be allowed to wear the Hells Angels' insignia.
Police Association president Greg O'Connor warned at the time that the gang was expanding its reach in Nelson via closer relations with the Red Devils.