Motorists in Melbourne can buy unleaded petrol for less than $1 a litre for the first time in four years, but more than 100 service stations are still charging $1.60.

The coronavirus-induced economic slowdown has caused demand for oil across the world to plummet, dropping its price by about 50 per cent this year and making it far cheaper to produce petrol.

This should have led to cheaper prices at the bowser but some service stations are profiteering by keeping consumer prices high.

Rod Sims, chairman of the Australian Competition and Consumer Commission, has a blunt message for the hundreds of service stations across the city charging exorbitant prices: "Bring your prices down."