SwissMedic said: "For the vaccine from AstraZeneca, the data available and evaluated to date are not yet sufficient for approval.
"In order to obtain additional data on safety, efficacy and quality, data from new studies are required."
The move runs counter to the decision made by the European Union's drug watchdog - which Switzerland is not a member - to green-light AstraZeneca's Covid jab last week.
But there is a growing list of EU countries refusing to allow the use of the vaccine in older people.
France, Germany, Italy, Sweden and Poland have all advised against use for people over a certain age.
SwissMedic said it will wait for further information from two clinical trials in North and South America before making a final decision.
Comment: Meaning the America's are knowingly using their population in one massive experiment:
It has vowed to move swiftly once the data is available.
Switzerland has approved the BioNTech/Pfizer and Moderna coronavirus vaccines for use.
Despite its wealthy medical industry, Bern has been sluggish with its attempt to roll out coronavirus jabs.
It has only managed to administer 315,000 doses of vaccines, at a rate of 3.64 per 100 people.
Comment: Switzerland was also slow to enforce a lockdown, and even then it only did so with limited restrictions. And now, thanks to Switzerland's constitution, a vote has been triggered to roll back any restrictions because the majority of people see them as an unnecessary threat to personal freedoms.
Despite a number of European countries moving against the AstraZeneca vaccine, its makers continue to defend the jab.
Comment: Naturally...
Director Andrew Pollard, of the Oxford Vaccine group, said people should be reassure that the vaccine is safe and producing a "strong immune response" for older people.
He said: "I think the first really important point is that the European Medicines Agency has approved the vaccine for use in all ages in all countries in Europe.
"Our regulator, the MHRA, has approved for all ages and another 25 or so regulators elsewhere in the world have also approved the vaccine for all ages.
Comment: Note that many of these approvals were pushed through with emergency legislation, meaning governments acknowledged that they did not meet the usual safety criteria.
"But individual countries have their own committees, and they have to look at what vaccines they have available, what they make of the data and what's best for their population. And so that's obviously up to them."
As Europe lags behind Britain's vaccine, Commission boss Ursula von der Leyen accused the UK of cutting corners over safety.
She said Britain had only managed to get a head start over the bloc after compromising on "safety and efficacy" tests.
The German said leaving it late "was the right decision", adding: "It's a gigantic responsibility."
Britain secured a three-week head start over Brussels by taking responsibility for any future liabilities for vaccines.
Downing Street said the jabs were safe.
Comment: It seems that we're seeing a significant push back from some nations, because India recently rejected Pfizer's vaccine and also because of concerns over serious side effects and a lack of safety data: Pfizer's vaccine fails to meet India's safety standards
For insight into the risks involved, see: