As WA's new Premier Mark McGowan declared Western Australia's financial situation "the worst since the Great Depression" on Thursday morning, Rio Tinto Iron Ore released a statement promoting its job creation efforts in the state.

Development projects underway at Rio Tinto's new Silvergrass mine and its pre-existing West Angelas and Yandicoogina mines were expected to create more than 1000 construction jobs in the state, the company's statement said.

Construction at Rio's 16th Pilbara iron ore mine, Silvergrass, had been ramping up since the start of 2017 and was forecast to provide about 500 jobs during construction.

Development of a new deposit at the West Angelas mine was now nearing completion, with an estimated peak workforce of 120.