Geneva: Swiss voters approved a new surveillance law on Sunday, in a victory for the government which argued the security services needed enhanced powers in an increasingly volatile world.
The proposed law won 65.5 per cent support across the wealthy alpine nation, final results showed.
Switzerland's police and intelligence agencies have had limited investigative tools compared to other developed countries- phone tapping and email surveillance were previously banned, regardless of the circumstances.
But the new law will change that.
The government insisted it was not aiming to set up a vast data-gathering apparatus, similar to the one developed by the US National Security Agency that came into the public eye in part through former contractor Edward Snowden's revelations.
"This is not generalised surveillance," lawmaker and Christian Democratic Party vice president Yannick Buttet told public broadcaster RTS as results were coming in.
"It's letting the intelligence services do their job," he added.
Swiss defence minister Guy Parmelin had said that with the new measures, Switzerland was "leaving the basement and coming up to the ground floor by international standards."
Parmelin insisted the Swiss system was not comparable "to the United States or other major powers", who have struggled to find the right balance between privacy and security.
Phone or electronic surveillance of a suspect will only be triggered with approval by a federal court, the defence ministry and the cabinet, according to the law.
Bern has said these measures would be used only a dozen times a year, to monitor only the highest-priority suspects, especially those implicated in terrorism-related cases.
The law was approved by parliament in 2015, but an alliance of opponents, including from the Socialist and Green parties, got enough signatures to force today's referendum.
The poll was part of Switzerland's direct democracy system, in which votes are held on a wide range of national issues four times a year, and even more frequently at regional and municipal levels.
Just 43 per cent of voters took part in today's poll, a slightly lower mark than recent referenda when flashpoint issues like immigration were on the ballot.