A national system of road-pricing - charging motorists according to how far they drive in exchange for cheaper petrol prices and registration fees - is likely to be explored in a study commissioned by the federal government.

The interest in a potential road pricing system comes amid business calls for new methods of curbing chronic traffic congestion in Sydney.

In an interview, the Federal Minister for Major Projects, Paul Fletcher, said the government would respond to a recommendation from advisory body Infrastructure Australia that it commission a study into how a road pricing scheme would work.

"We don't think this is happening overnight but the policy advice has been fairly consistent on it, so the immediate question that we need to look at is whether it makes sense to take the next steps that Infrastructure Australia has recommended which is doing a detailed study on the design," Mr Fletcher said.