Major Swiss companies will be required to review pay gaps between male and female staff from next year under rules adopted by the government on Wednesday, part of a bid to close a gender divide in one of the world's richest countries.

Despite its high quality of life, Switzerland lags other developed economies in female pay and workplace equality.

Swiss women earn roughly 20% less than men. While that is an improvement from about a third less in 1991, the discrimination gap — meaning differences that cannot be explained by rank or role — has actually worsened since 2000, government data show.

That helped prompt hundreds of thousands of women to go on strike in June to highlight the nation's poor record on women's rights.

The cabinet agreed on Wednesday to require companies employing 100 or more people to conduct internal analyses of pay gaps between men and women from next year, with studies to be completed by June 2021.

They will be required to undergo an external audit of the numbers and present them to staff.

The rules cover just under 1% of Swiss companies that employ 46% of workers in Switzerland. Companies that find a gap must repeat the exercise every four years.

Switzerland was the second to last European country to embrace women's suffrage in 1971, more than half a century after Norway, Germany, Canada and the United States.