The Swiss branch of the environmental organisation, Greenpeace, has called on the government to rethink its nuclear waste policy.
The call comes as the House of Representatives prepares to debate a revision of the country's nuclear energy law on June 19.
Greenpeace claims that a proposed modification of the existing law could lead to the exportation of nuclear waste to Russia.
The organisation says it is lobbying parliamentarians not to support a declaration of intent signed by the Swiss nuclear industry and Russian authorities in 1998.
Around 20 Greenpeace activists - dressed in white and wearing masks - demonstrated outside the parliament building in the federal capital, Bern, this week as parliamentarians arrived for the summer session.
"We are calling on authorities to ban the reprocessing [of nuclear waste] and to prohibit the export of Swiss nuclear waste to foreign countries," said Greenpeace spokeswoman Eva Geel.
Switzerland already sends nuclear waste to Britain and France but is contractually obliged to take this back once it has been reprocessed.
However, under the deal signed with the Russians, nuclear waste would not be returned to Switzerland for final storage, Geel told swissinfo.
"If nuclear waste comes back to Switzerland and has to be stored for thousands of years, it will destroy the image of clean nuclear energy. So the obvious solution for them is to send it to Russia and forget about it," she added.
But Werner Buehlmann, head of the nuclear energy division at the federal energy office, said nuclear waste would not be exported to Russia unless "very strict conditions" had been fulfilled.
"One of these conditions is that the foreign country must already have final storage facilities with an internationally accepted level [of security]," Buehlmann said.
"The conditions for the export of nuclear waste must be fixed in a bilateral agreement between that state and Switzerland, and we think that for the foreseeable future Russia will not be a candidate to fulfil our obligations in that field," he added.
by Scott Capper and Ramsey Zarifeh