Greenpeace says Russian authorities have not lifted charges of piracy against 30 activists, despite pledging last week to charge them with the lesser offence of hooliganism instead.
New Zealanders Jonathan Beauchamp and David Haussman are among the group arrested over a protest at an Arctic drilling platform in September.
Greenpeace New Zealand campaign manager, Carmen Gravatt, says when the detainees were brought before Russia's Investigative Committee last week the piracy charge was not withdrawn - instead, each of them was served with an additional charge of hooliganism.
She says they now stand accused of both offences, which carry a maximum sentence of 15 and seven years respectively.
"We've got no idea why they haven't taken the piracy charges off. We reject both the piracy and hooliganism charges, these people are neither pirates nor hooligans, they were involved in a peaceful protest," she says.
Greenpeace also says the protesters are being moved from a detention centre in the northern city of Murmansk to a prison in St Petersburg, about 1,000km away.
The detainees say they are being held in cold and inadequate conditions in Murmansk.
The legal system in Murmansk was also struggling to cope with the number of interpreters involved, the BBC reports.
Greenpeace International says it will be easier for relatives and consular officials to reach the detainees in St Petersburg.
Lawyers for the lobby group say they understand the group will be moved by train and could be in St Petersburg in the next 24 hours.