Greenpeace is calling on the Government to turn around the world's largest seismic survey ship, preventing it from searching for oil in the Taranaki Basin.
The Amazon Warrior arrived in Kiwi waters on Saturday ahead of its search for oil on behalf of Austrian company OMV.
Greenpeace climate campaigner Kate Simcock says it appears the Government is yet to approve the vessel's permit to seismic blast for oil and gas this summer.
With the Taranaki Basin recently found to be New Zealand's only feeding ground for blue whales, she said it was not too late to turn the Amazon Warrior around.
"We understand [the vessel's operator] is proposing up to three months of constant blasting, every 10 seconds, 24 hours a day," she said.
"The impacts on blue whales in this area are likely to be torturous, interfering with their communication and feeding."
She said Prime Minister Jacinda Ardern had called climate change her generation's nuclear-free moment and challenged her to act against oil exploration.
"Going nuclear-free meant stopping the nuclear ships," she said.
"Taking action on climate change means stopping the oil exploration ships. We'd like to see the Prime Minister back up her bold words with strong action."