Police said two men aged 22 and 19 were arrested and charged with assaulting police and a 20-year-old woman was arrested for obstructing a public space.
Protesters are blocking the doors ahead of a petroleum exploration conference.
Protester James Millsworkman says they also want to see no more oil conferences at Wellington City Council venues.
Millsworkman says one protester has been injured after being pushed up against a wall.