Property prices will plunge by up to 9 per cent and up to 270,000 jobs will be lost, with unemployment to peak as high as 11 per cent, modelling by the Victorian government on the impact for the state reveals.

The "devastating and unprecedented" modelling backs up the Reserve Bank of Australia, which expects national unemployment to peak as high as 10 per cent in June, before the economy begins to bounce back, with fears unemployment may remain above 6 per cent for two years.