Poorly integrated foreigners could have their residence permits revoked and even face deportation.
The Senate on Wednesday followed the House of Representatives in approving a proposal by the rightwing Swiss People's Party, despite opposition by the centre-left.
A second motion imposing stricter pre-conditions for naturalisation applicants was also passed. Successful candidates must demonstrate a good level of integration and have a good knowledge of one of the four national languages, it said.
Justice Minister Eveline Widmer-Schlumpf pointed out that the law on naturalisation was already in the process of being modified by her ministry, independently of the current parliamentary moves.
She said integration and language skills would be the central focus of the amended law, rendering the latest motions superfluous.
swissinfo.ch with agencies
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