Wellington ACC staff arrived at work this morning to find six tonnes of dairy waste blocking the entrance to their office.
It was part of a Greenpeace protest against ACC's apparent involvement in a controversial irrigation scheme.
The dairy sewage, including cow urine, was wheeled into central Wellington early on Wednesday morning.
Greenpeace protesters blocked the main entrances to ACC with heavy-duty tanks to send the message that river pollution is not okay.
"ACC looks set to throw millions of taxpayer dollars at the controversial Ruataniwha dam that will expand the industrial dairying and pollute our rivers, and we think that's just taking the piss," says Greenpeace agriculture campaigner Genevieve Toop.
The Ruataniwha water storage scheme is yet to get the final go ahead from Hawke's Bay Regional Council -- which is in talks with potential investors.
Greenpeace believes that includes ACC.
"They've refused to deny their involvement with the Ruataniwha dam, which is pretty good signal they're set to find this controversial and polluting scheme," says Ms Toop.
But ACC told Newshub it doesn't comment on things it "may or may not invest in".
After eight hours, the Greenpeace protesters piled their waste back onto a truck, confident their message had been heard by ACC.
As for the six tonnes of dairy waste -- Greenpeace won't comment on where it came from nor where it's going, but say it will be disposed of safely and away from New Zealand's rivers.