Swiss voters have rejected a proposal to give the neutral country's laws priority over international law, a move that critics claimed would have deeply damaged its global standing and hurt its economy.

Some 66% of voters and all of its cantons voted against the "Swiss law, not foreign judges" measure in a national referendum, the government said.

The measure, backed by the right-wing Swiss People's Party (SVP), called for a provision to be added to the national constitution giving it explicit precedence over international agreements.

Where there is a clash between the two, Switzerland would have had to alter its international obligations so they complied with its constitution or quit the international agreement.

Backers argued that neutral Switzerland's historic autonomy was being watered down by its participation in international agreements covering areas such as environmental protection, police cooperation, air transport and trade.

Their campaign said that such agreements endangered the long tradition of direct democracy in Switzerland, where citizens have the final say on political decisions via referendums.

Debate over whether sovereignty has been eroded has intensified in recent years as Switzerland has struggled to clarify its relationship with the European Union and is currently governed by a tangle of bilateral pacts.

The SVP, the largest party in the Swiss parliament, said its proposals would empower citizens and free them from interference from international bodies such as the EU.

They were opposed by the Swiss government, business groups and most other parties, who said the proposal would force Switzerland to cancel existing treaties, weaken human rights protections and hurt its economy.

They said a "yes" vote would result in Switzerland having to renegotiate thousands of treaties it has signed, undermining an open economy that is highly dependent on global trade.

Swiss voters have also rejected a proposal to subsidise farmers who let the horns on their cows and goats grow rather than removing them with a red-hot iron in a procedure which critics say causes pain.

Three-quarters of Swiss cows, a national symbol and tourist attraction, are dehorned or genetically hornless.

Hornless animals are easier and cheaper to keep because they cause fewer injuries and need less space.

They do not have to be tied in separate pens to prevent accidents, but this means farmers can keep fewer animals.

The initiative to preserve "the dignity of livestock" was led by farmer Armin Capaul, who has sparked a national debate on animal rights following a campaign which began nine years ago after he "listened" to his herd.

But the campaign was defeated, with nearly 55% of Swiss voters rejecting the proposals in the final result, the Swiss government said.

The government had opposed the motion, which would have enshrined subsidies into the constitution, but agricultural workers were split, with even the Swiss farmers' union refraining from giving a recommendation to its 52,000 members.