A man has locked himself to a silo on a Waikato pig farm in a protest over factory farming.
Open Rescue member John Darroch said he was prepared to stay at the Cambridge property for up to two days.
Supporters with banners, placards and pig costumes were also outside the farm.
Mr Darroch said that over the past month he had visited several pig farms in Waikato and been shocked and saddened by what he had seen.
"It was heartbreaking to see sows who had just given birth. They were completely unable to carry out any of their natural behaviours and could do no more than stare as we walked around," he said.
"Today's action is not aimed at this particular farm, which is acting lawfully. It is aimed at an industry which is inherently cruel, and a government which refuses to act."
Mr Darroch said New Zealand Open Rescue believed the new draft Code of Welfare for pigs was inadequate and still allowed sows to be confined in crates for their entire lives until 2013, limited to 20 weeks by 2013, and 10 weeks by 2018.
"New Zealand Open Rescue wishes to put pressure on Minister of Agriculture David Carter to fix up the loopholes in the Animal Welfare Act which allow Codes of Welfare to be implemented that to do not meet the basic principles of the Act."