About 30 protestors remain on board a ship in Timaru Harbour this evening, in an attempt to stop it sailing.
The activists stormed the vessel this morning, some attaching themselves to various parts of the ship - including the mast.
The 'Skandi Atlantic' is preparing to meet up with an Austrian oil rig off the coast of Taranaki.
"This is all about preventing that drill rig from getting into position and drililng new oiil and gas wells," protestor and Greenpeace spokesperson Sophie Schroder said.
"They need this support vessel to be able to get their anchors in place and be able to start drilling."
OMV, the company behind the drilling has been the target of multiple recent protests on both sides of the Tasman.