Full-time workers who drive between Melbourne's suburbs and the CBD spend on average $6000 to $10,000 a year more on commuting than workers who take public transport, an analysis has found.

The report, Commuter costs and potential savings, compared public transport and car commuting costs in seven Australian capital cities and found driving was the more expensive option in all of them.

It found a resident of outer Melbourne who works five days a week in the CBD, does not own a car and commutes 25 kilometres by public transport would spend $17,949 less a year on commuting. An inner-city resident living five kilometres from the city who owns a small car but commutes by public transport would save $5772 a year.

The analysis is based on a range of commuting costs for someone who works 231 days a year. It compares the cost of three scenarios - a worker who owns a car and drives to work five days a week; one who owns a car, but catches public transport to work; and one who does not own a car.