About 100 supporters of the so-called Arctic 30 have protested in Sydney's Circular Quay against the detention of the Greenpeace activists in Russia.
Family members and friends of Australian Colin Russell and Sydney resident Alex Harris released 30 white doves to mark 60 days since their arrest.
The 28 activists and two freelance reporters attempted to scale an oil platform operated by Russia's energy giant Gazprom in September.
Russia's Investigative Committee has announced it will apply for a three-month extension to the detention of the group, which has been transferred from the northern port of Murmansk to a detention centre in Saint Petersburg.
The cousin of Sydney resident Alex Harris says she's been shocked by the turn of events.
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"The last time I saw her before she left I told her to be safe to have fun and this new adventure would change her life," Gemma Dallyn said.
"Needless to say I didn't have prison in mind."
Greenpeace says their crew members are suffering severe weight loss from the harsh conditions.
"[He is] sharing his cell with rats, [he is] very cold and not allowed out for 23 hours a day," Colin Russell's wife, Chrissie said.
Mr Russell's 24-year-old daughter Maddy broke down on Saturday morning as she spoke about not having her father back by Christmas during a support rally near the Sydney Harbour Bridge.
"We've had only one call in the whole 60 days since this happened.
"I had a hope in the back of my mind that he would be home in time for Christmas and I don't know what to make of it now."
