The hearing on the detention of the eighth activist was still continuing.
The court was on Sunday holding simultaneous hearings in several different courtrooms to decide whether to extend the detention for the activists.
The hearings were running behind schedule, and Greenpeace said there were problems with English and Dutch translation.
Diplomats from several countries were in attendance.
The total of 30 detained crew members of Greenpeace's Dutch-flagged Arctic Sunrise icebreaker include six British citizens, four Russians and nationals of 16 other countries including Argentina, Italy, France, Australia and New Zealand.
Russian investigators have accused the activists of piracy after Saarela and another activist tried to scale state energy giant Gazprom's Prirazlomnaya oil platform in the Barents Sea.
The group has denied committing piracy and accuses Russia of illegally boarding its ship in international waters.
President Vladimir Putin has said that the activists "are of course not pirates" but stressed they had broken international law by getting dangerously close to the oil rig.
Charges of piracy carry a maximum prison term of 15 years but the Investigative Committee said that the charge against the group could be reduced in the course of the probe.
Among those detained for two months is the vessel's captain, Peter Willcox, who was also the skipper of Greenpeace's Rainbow Warrior ship, which French secret services bombed and sank in New Zealand in 1985.
Another is photographer Denis Sinyakov, a former staff photographer at AFP and Reuters who was working for Greenpeace as a freelancer.
The Netherlands government called on Moscow to release the activists immediately and said it was considering legal action.
The arrests also sparked outrage from Russian and international rights activists, with Reporters Without Borders saying Russian investigators were "criminalising both journalists and environmental activists".
'Cellmate with Russians accused of robbery'
Fourteen of the 22 detained are being held in a pre-trial detention centre in Murmansk, while the other eight have been transferred to the nearby city of Apatity.
In violation of the law according to which foreign suspects should be held separately from Russian nationals, a British activist is being held with two Russians suspected of robbery, said Irina Paikacheva, the head of a state-connected regional prisoner rights watchdog.
"That is a violation," she told AFP. Other activists are likely to get cellmates from ex-Soviet countries because keeping suspects by themselves would also be a violation of the law.
She noted that according to Russian law, the Greenpeace activists cannot be held together because they have all been detained on the same charges.
One of the detained activists suffers from asthma, she added.
Overall, the activists are being held in "satisfactory conditions," said Paikacheva. "The food is decent. The cells are rather spacious."
The detention centres where suspects are held before trial in Russia are called Investigative Isolators (SIZO) and do not differ much from common Russian jails notorious for their filthy conditions and prisoner abuse.
- AFP
