The Swiss on Sunday flatly rejected a call for dramatic immigration cuts in the name of saving the environment, amid charges the initiative was xenophobic and a threat to Switzerland's economy.

Final results showed 74.1 percent of Swiss voters spurned the so-called Ecopop initiative, which called for slashing immigration to reduce population growth and urban pressure on the Alpine nation's idyllic landscape.

The Swiss also resoundingly rebuffed bids to scrap special tax breaks for rich foreigners living but not working in the country and to significantly hike the country's gold reserves.

Just under half of eligible Swiss voters cast their ballots in Sunday's vote, which is average in the country where the people are called to the polls every three months to voice their opinions on a seemingly endless range of issues as part of the country's famous direct democratic system.

Although opinion polls had hinted the Swiss would vote "no" across the board, supporters of the Ecopop initiative had voiced hope silent support from the masses would lead to a surprise win.

That happened less than a year ago, when voters in February caught many off guard by narrowly voting to impose quotas for immigration from the European Union, throwing non-member Switzerland's relations with the bloc into turmoil.

- Threat to Swiss economy -

The country has been scrambling ever since to figure out how to implement that result without pushing the EU, its main trading partner, to rip up a long list of bilateral agreements.

The government, all political parties, industry, employers and unions had urged voters to reject Ecopop, amid warnings its acceptance would fan the flames of the controversy with Europe.

Opponents had also slammed Ecopop as "absurd" and a threat to Switzerland's economy which depends heavily on immigrant labour.

"The verdict is clear," insisted Swiss Justice Minister Simonetta Sommaruga, who will take over the country's rotating presidency on Wednesday.

But she stressed Sunday's results did not bring into question February's EU immigration quota decision.

Foreign nationals already make up nearly a quarter of Switzerland's eight million inhabitants, official statistics show.

According to Ecopop, immigration is adding 1.1-1.4 percent annually to the Swiss population, putting the country on track to to have a population of 12 million by 2050.

The campaign wanted to cap immigration's contribution to population growth at 0.2 percent, which would mean a population of 8.5 million by the middle of the century.

- 'Civilisation collapse?' -

"What I'm worried about is a civilisation collapse," Philippe Roch of the Ecopop committee told RTS after the results became clear.

"But clearly this text did not convince voters," he acknowledged.

As it became clear that voters had massively rejected the initiative, sarcastic tweets flourished carrying the hashtag #Ecoflop.

In all, 59.2 percent of voters also rejected the bid to scrap tax breaks for rich foreigners living but not working in Switzerland, who today can choose to be levied on their spending rather than income.

Switzerland counts 5,729 millionaires and billionaires with foreign passports, who together pay around one billion Swiss francs ($1.04 billion, 830 million euros) in taxes annually.

That is a far cry from what they would have paid had they been levied at the same percentages as average Swiss taxpayers, according to the left-leaning parties and unions behind the initiative.

But backers of the system insist wealthy foreigners contribute substantially to Swiss tax coffers and inject huge sums directly into the local economy, warning many would leave the country if they faced higher taxation.

"People can count," Christian Luescher, a parliamentarian from Geneva for the Liberal Party told RTS as the results came in.

He pointed out that Geneva, where most beneficiaries of the current system live, risked losing hundreds of millions of Swiss francs in tax revenue alone if the wealthy residents packed up and left.

More than three-quarters of voters also heeded warnings from the Swiss National Bank that forcing it to hoard gold and banning it from selling the precious metal would tie its hands and could have disastrous consequences.

Analysts had warned the bank would be forced to buy around 10 percent of the annual global gold production until 2019 to meet that requirement.