The Swiss Federation of Trade Unions has begun collecting signatures to force a vote on introducing flexible retirement from the age of 62.
The text of the initiative was published on Tuesday. The federation now has until December 2006 to gather the 100,000 signatures needed.
The retirement age for men currently stands at 65, with women entitled to draw an old-age pension from 64.
The government is concerned that the state old-age pension scheme will eventually collapse as the number of workers for every pensioner falls, and is looking at ways of reforming it.
Interior Minister Pascal Couchepin has proposed raising the retirement age to as high as 67.
But the trade unions want to give employees the right to stop work at the age of 62 and still receive a full pension.
Their plan would cost up to SFr1 billion ($0.8 billion) annually.
The federation said that the public’s rejection of a pension revision plan in May 2004 "had shown clearly that the vast majority of Swiss did not want any cuts to their pension entitlement or increase in the retirement age, but a social solution allowing a flexible retirement age".
Former Interior Minister Ruth Dreifuss has lent her support to the initiative. The federation quoted her as saying she wanted "to see the numerous promises of government and parliament to introduce a social, flexible retirement age finally implemented".
Three previous attempts over the past 15 years to introduce a flexible retirement age have failed at the ballot box.
This latest trade union proposal comes amid continuing discussions over ways to secure the funding of the compulsory state-run pension scheme.
The Employers’ Association last year called for the retirement age to be raised to 66 to cover pension costs and spur economic growth.
There are concerns that the system is collapsing as the number of pensioners grows while the number of contributors decreases.
The state old-age pension scheme, which is part of a three-tier social security system, is financed partly by contributions from employees and employers and other tax revenues.
swissinfo with agencies
The current retirement age is 64 for women and 65 for men.
The initiative "for a flexible pension age" is calling for the right of all employees to draw a pension from age 62.
People earning less than SFr116,000 per annum would not see their pension reduced if they opted for early retirement.
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