Carl Scott from the Dunedin Animal Rights Collective scaled a 20m high silo tower at Bloems' farm on the Otago Peninsula early Wednesday morning, Radio New Zealand reports.

He hung a banner from the silo saying Vote to Stop Factory Farming.

Other members of the group on the ground held placards calling for the public to vote for those political parties which are pledging to change animal welfare codes.

They are the Greens, Labour and Internet-Mana.

Police said Mr Scott came down voluntarily without incident and was arrested for trespass but other charges are being considered.