Greenpeace says its ship, the Arctic Sunrise, is still being held in Murmansk, Russia.
The organisation wants the vessel back, but did not provide any further details.
Thirty people aboard the icebreaker were taken into custody after an attempt was made to board an oil platform owned by Gazprom in the Arctic on 18 September. The ship was towed to Murmansk by a tug.
All 30 detainees were freed this week after the Russian parliament passed an amnesty on hooliganism on 18 December. Departure visas were issued to them in St Petersburg on Thursday and Friday.
NZ detainees now back home
The two New Zealanders who were detained, Jonathan Beauchamp and David Haussmann, are back in the country.
The head of Greenpeace in New Zealand says the fight to save the Arctic from oil drilling has gained millions of additional supporters thanks to the so-called Arctic-30.
Greenpeace New Zealand chief executive Bunny McDiarmid says two New Zealanders are pleased to be home and are looking forward to spending time with their families.
But she says the group should never have been arrested, and their campaign has millions more supporters now, as a result of what the 30 people have been through.
The Arctic Sunrise was built as an icebreaker in 1975 and was chartered by Greenpeace in 1995.