Protesters have cost a Brazilian oil company an estimated $500,000 by forcing it to shut down its oil and gas exploration off the East Cape for two-and-a-half days.
Last Sunday, activists swam in the path of the vessel doing seismic surveying for Petrobras, which has been given a permit by the Government to explore the Raukumara Basin.
The Petroleum Exploration and Production Association says seismic surveying costs about $250,000 a day.
A protest flotilla, which had been following the vessel since surveying started two weeks ago, has returned to shore after being issued exclusion notices.
A spokesperson for the protesters say they plan to go back to sea.