Geneva (dpa) - Swiss voters will decide in a referendum on Sunday whether Swiss businesses should be held to account for environmental and human rights violations that are committed abroad.

Firms would become liable not only for their own actions, but also for foreign subsidiaries, suppliers and business partners, according to the so-called "Responsible Business Initiative" that is backed by advocacy groups such as Greenpeace and Amnesty International.

Switzerland is home to a number of global corporations that are among the largest in their field, including food maker Nestle, commodity group Glencore and pesticide producer Syngenta.

Although the government in Bern backs the idea of protecting rights and the environment along the production chain, it opposes the initiative.

The new policy would create legal uncertainties and would put Swiss jobs at risk, the government argues.

The backers stress that the international liability rules would only apply to large corporations, and not to smaller firms.

A rejection of the initiative would pave the way for the government's alternative proposal, which foresees stricter due diligence on issues such as child labour and mining in conflict zones, but no global liability scheme.

Swiss voters are also casting their ballots in a second referendum on curbing the defence industry on Sunday.

Voters are asked to say yes or no to banning major investors from funding any companies that generate more than 5 per cent of their revenues from combat weapons and weapons parts.