GENEVA (AP) — Swiss voters are casting final ballots in a referendum on a measure that could stiffen penalties against companies that are based Switzerland if they violate human rights or harm the environment abroad.

The federal government opposes the initiative titled “Responsible companies — to protect people and the environment," championed by left-leaning groups and some big civil society organizations, asserting that it goes too far. Parliament has proposed a countermeasure that would also boost scrutiny of such companies’ actions.

Polls suggest a close contest in the vote — mainly conducted by mail-in balloting — that ends Sunday. The referendum had originally been planned for May, but was delayed because of the coronavirus.

In a first, the measure could make large Switzerland-based companies liable in the country's courts for their flawed operations or those of their subsidiaries and subcontractors in foreign nations, unless they are able to show that they conducted proper due diligence beforehand.

The measure would require Swiss-based companies to better verify their activities in foreign countries and could make them more liable for any damage caused. It could potentially affect multinationals like mining and minerals giant Glencore, agribusiness company Syngenta, and cement powerhouse LafargeHolcim — which have at times faced criticism over their activities abroad.

Parliament’s alternative, which would take effect automatically if the measure fails, wouldn't require companies to answer to Swiss courts, and would focus on issues like mining of minerals drawn from conflict zones or child labor. It also seeks more cooperation among countries on such matters.

The government believes the measure would weaken Switzerland’s economic competitiveness. Organizations like Amnesty International, Greenpeace and the Swiss watchdog group Public Eye back the proposal.

Another measure being considered Sunday would ban the financing of any weapons destined for export, from handguns to assault rifles to tanks, but polls suggest that idea was poised to be rejected.