Hundreds of people have marched up Auckland's Queen Street and are staging a sit-in outside the New Zealand Petroleum Summit to protest deep sea oil drilling.
The hikoi against started in Northland on Saturday and reached Auckland today.
The police had to stop traffic in the central city as about 500 people marched towards the Sky City convention centre, where they are staging a sit-in outside.
The Waiho Papa Moana hikoi, or Stop Deep Sea Oil Drilling protest, includes iwi representatives from Northland's west coast and Oil Free Auckland protesters.
Hikoi organiser Mike Smith said there was strong support for their core message, which was to prevent deep sea oil drilling and seismic testing in New Zealand.
Protesters were targeting Norwegian oil firm Statoil in particular, he said.
"They begin work in December. They're going to start seizmic testing, which we know kills marine mammals.
"That's one of the reasons we're targetting Statoil, because their action's imminent."
Mr Smith said he hoped the turnout today would show the extent of opposition to mineral exploration in this country.