GENEVA (AFP) - Swiss voters on Sunday overwhelmingly rejected a referendum calling for an end to the country's military draft, with 73 per cent casting ballots against the plan, exit polls showed.

In a country whose part-time army is ingrained in the national image - and seen abroad as being as Swiss as cheese, chocolate and Heidi - voters bucking a post-Cold War European trend against conscription was no surprise.

But the exit polls by the gfs.bern institute for public broadcaster RTS showed that opposition to the plan was a full 10 percentage points higher than forecast over recent days.

Armed neutrality has been the cornerstone of Switzerland's defence policy for almost two centuries, with soldiers straddling the civilian and military worlds, keeping their weapons at home when they are not in training.

"Abolishing military service would break the genuine link uniting the people and the army," insisted Defence Minister Ueli Maurer ahead of Sunday's vote.

But there is also an anti-military undercurrent in Switzerland, which has not been invaded since the Napoleonic Wars of the early 19th century, despite major scares during World Wars I and II.

Direct democracy is another bedrock of Swiss society, and referenda are held several times a year on a range of federal and local issues.

Th exit polls showed that 27 per cent of voters backed the anti-conscription plan on Sunday, slightly down on the forecast score.

The anti-draft camp, spearheaded by pacifists and left-wing parties, had not expected victory on Sunday, but had been eyeing a symbolic score of at least 30 per cent.

They were mindful of their high point in 1989, the year the Iron Curtain fell, when a vote on abolishing the army outright mustered a surprising support of 36 per cent. In 2001 they garnered 21 per cent.

"Compulsory military service is a tool created for wars of the past," said Mr Tobias Schnebli of the anti-military group GSoA, telling AFP that a country in the heart of Europe faced no serious threat of invasion.

The plan was opposed by the political right and centre, as well as parliament and Switzerland's cross-party government, and not simply due to cliches about the army being as Swiss as its pocketknives.

Male Swiss citizens aged between 18 and 32 begin service with a seven-week boot camp and take six 19-day refresher exercises over ensuing years. Since 1992, non-military service, for example in environmental projects, has been available for conscientious objectors.

Supporters of the status quo argue that other European nations which axed conscription have struggled to fill their military ranks, even with unemployment high amid the economic crisis, denting their defence capacity.

While Switzerland is ringed by friendly nations, draft supporters say the Swiss army in its current shape is essential in a world of morphing threats.

The army also plays a key role in providing security at international summits, as well as disaster relief.

Supporters also argue that the draft helps cement a country with three main language groups - German, French and Italian - and also cuts across class lines.

Critics reject those arguments, arguing that language groups stick together when in uniform, women do not have to serve, and almost half of those called up do not start or complete their training on health or other grounds, with middle-class urban dwellers more able to avoid it.

Men who do not serve pay a special tax of 4 per cent of their salary instead.

Still, the Swiss army is no longer the giant it once was.

A string of military reforms for budgetary and strategic reasons have repeatedly reduced its pool of trained troops from 625,000 in 1961 to today's 155,000.

By 2016, the figure is set to be 100,000 - a leaner and fitter force, supporters say.

But critics say that is still way too big in a nation of eight million.

Neighbouring Germany, for example has 10 times the population and 183,000 active troops.