Greenpeace's Russel Norman is one of a group of protesters facing charges after swimming in front of the oil prospecting ship the Amazon Warrior yesterday.
Mr Norman and three others were served with charge sheets after returning to land today, accused of breaching zone restrictions around petrol-related work operations at sea.
The Amazon Warrior is studying underwater areas off the Wairarapa coast for oil companies Statoil and Chevron.
Russel Norman said it beggared belief that the government was prosecuting him to protect the interests of oil companies.
"We've all agreed that we need to limit greenhouse gas emissions and that means we can't even afford to burn the existing fossil fuel reserves," he said.
"So what on earth is the government doing by using the full force of the law to try to expand the amount of fossil fuel reserves in the world already."
Mr Norman will appear at Napier District Court on 10 May.