Some 70 percent of those who voted rejected the proposal, according to a forecast by the gfs.bern polling firm, which was in line with earlier predictions of a solid majority against.

Leftist voters backed the proposed that that would put in the constitution an engagement not to use more natural resources than the Earth's limits.

But the government and right and centre right parties opposed the measure saying it would endanger economic growth.

Greens' leader Margot Cauderna lamented the outcome, telling RTS television a vote in favour would have given parliament a chance to "seek new ideas to link ecology and social accessibility."