The families of two Canadian Greenpeace activists detained in Russia over an Arctic oil drilling protest pleaded Wednesday for Ottawa to further pressure Moscow to release them.

The Netherlands brought a case against Russia to the International Tribunal for the Law of the Sea, while the leaders of Germany, Britain and others have spoken out against the detentions.

But Ottawa has remained silent on the matter, which involves Canadians Paul Ruzycki and Alexandre Paul.

"Governments around the world are speaking out about this at the highest levels. Canadians are waiting for their government to voice its concern," Greenpeace Canada executive director Joanna Kerr told reporters.

The group and the men's families appealed in a statement to the Canadian government "to do everything within their power to secure the two men's safe release."

A government spokeswoman said Minister of State for Foreign Affairs Lynne Yelich had met with Greenpeace and "addressed their views directly," but offered no details, citing privacy laws.

The official said consular services were also being provided to both Ruzycki and Paul.

Moscow has sparked an international outcry over its heavy-handed response to the incident, in which two Greenpeace activists scaled a state-owned oil platform in September to protest against Russian energy exploration in the Arctic.

Ruzycki and Paul were among 28 crew members and two journalists aboard the Dutch-flagged icebreaker Arctic Sunrise in the northern Murmansk region who were detained on piracy charges, which prosecutors later reduced to hooliganism.

"My brother is not a pirate or a hooligan," said Ruzycki's sister Patti Stirling at the Parliament Hill press conference also attended by Alexandre Paul's mother.