Greenpeace New Zealand says it is a relief that Russian President Vladimir Putin does not consider 30 detained activists to be pirates.
The activists' ship Arctic Sunrise was seized and towed to shore late last week after two people tried to scale a platform to protest against Russian plans to drill for oil in the Arctic.
The activists, including two New Zealanders, have been detained in Murmansk.
Vladimir Putin says they are obviously not pirates but has suggested they may have broken international laws.
Greenpeace New Zealand executive director Bunny McDiarmid says the Russian authorities cannot continue to detain the ship and crew if no charges are laid.
In Russia, piracy is a crime punishable by up to 15 years in jail.
Ms McDiarmid says the crew will appear at a court hearing in Murmansk on Thursday.