Tests on ten dead birds found in Switzerland, six of them swans, have come up negative for all forms of bird flu.
But the Federal Veterinary Office said on Friday it was important to remain vigilant as wild birds carrying the virus might still be found in Switzerland.
"All the analyses done on dead birds in Switzerland are negative: the animals did not die of bird flu," the office said in a statement.
"No form of bird flu was found, including H5N1," added spokeswoman Cathy Maret.
The dead birds, which included six swans, a seagull and a heron, were found in five cantons including Zurich. The tests were carried out at Zurich University.
The government has advised people not to touch any birds found dead.
Around 600 swans die of normal causes every year in Switzerland, 300 of which are normally noted by the authorities, according to the veterinary office.
Heightened surveillance measures because of the threat of bird flu could be leading to a higher count of swans than normal.
Local vets will set up a protective zone around any discovery of a potential bird flu case.
Three European countries bordering Switzerland - Italy, Austria and Germany - have found the deadly H5N1 virus in birds.
France earlier reported that a dead swan found in the east did not have bird flu, but two dead ducks discovered close to a northern bird park were still being investigated.
On Wednesday, the Swiss cabinet decided to reintroduce a ban on keeping poultry outdoors. The ban comes into effect on Monday.
But not everyone considers the blanket ban a good idea. A number of zoos have already put in requests to allow their exotic birds to stay outside with the breeding season coming up.
Poultry farmers aren't convinced either that locking their animals up is the right solution.
Roland Weibel from Kagfreiland - a farm animal protection organisation which issues its own organic food label - told swissinfo that a previous confinement that ran for a few months at the end of last year did not adversely affect poultry sales.
But instead of a nationwide ban on allowing poultry outdoors, Weibel said bans could be restricted to areas considered at high risk, such as near lakes where migratory birds gather.
swissinfo with agencies
From October 25 to December 15 last year, the autumn migration period, Switzerland banned the keeping of domestic poultry outdoors.
Veterinary experts took samples from 800 migratory birds, but found no trace of bird flu.
Switzerland also banned imports of poultry products from affected countries and airport checks have been stepped up.
The anti-flu drug Tamiflu has been stockpiled to treat a quarter of the Swiss population.
To date, human cases have been reported in six countries, most of which are in Asia: Cambodia, China, Indonesia, Thailand, Turkey, and Viet Nam.
All human cases have coincided with outbreaks of highly pathogenic H5N1 avian influenza in poultry.
So far, Viet Nam has been the most severely affected country, with more than 90 cases.
Altogether, more than half of the laboratory-confirmed cases have been fatal.
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