With 101 votes against and 80 in favour, lower house lawmakers rejected a motion floated by the Green Party to join the Russian Elites, Proxies and Oligarchs (REPO) group launched in 2022 by the United States, Australia, Canada, the European Commission, France, Germany, Italy, Japan and Britain.
The task force is part of Western powers' drive to freeze and confiscate assets of individuals and entities that have been sanctioned over Russia's 2022 invasion of Ukraine.
The Swiss government had also recommended not joining the task force, arguing Switzerland already engages in extensive cooperation with the participating countries.
Justice Minister Beat Jans said that in an increasingly polarised world, Switzerland had an interest in maintaining a degree of independence in international relations.
"The advantage deriving from such a perspective can be seen, for example, with regard to the Ukraine peace summit, which Switzerland wants to organise and will organise," he said.
"Not participating in the REPO task force will make it easier for our country to continue to offer its good services."
Switzerland said last week it would host a two-day high-level conference in mid-June aimed at achieving peace in Ukraine.
Expectations of a major breakthrough are not high.
Russia has already said it will not take part in the talks, arguing that Switzerland, which has joined EU sanctions against Moscow, has given up its neutrality in the conflict.
(Writing by Dave Graham; Editing by Gareth Jones)
