The Australian Greens, which could hold the balance of power in the country’s upper house after Saturday’s election, have called for a halt to all new gas and coal projects, setting up a collision with the recently elected Labor government and the large fossil fuel export industry.

The Greens secured their best result in Australia’s general election on Saturday, winning at least three seats in the lower house and as many as 12 of 76 seats in the Senate, which could allow it to block Labor’s legislation if it was not supported by the conservative opposition.

It was not yet clear on Monday whether Labor would have an outright majority in the lower house. If it does not reach the 76 seats needed to govern on its own, the party will need to negotiate with the Greens or pro-climate independents on all non-bipartisan legislation.