Yang said toll roads have greatly benefited China's shipping industry. He blamed the overly large staff sizes on the high profits made from toll collection, which lead many people to compete for a job at one of the companies.

"The large staff sizes will add to the personnel costs of road management companies," he said. "That could lead to increased tolls and eventually raise shipping costs.

"In addition, collecting tolls has become such a lucrative business. But only a small group of people can share in the profits, and that will lead to social inequality."

Yang said transport authorities, as well as local financial, audit and price departments, should place the road companies under stricter supervision. He said achieving that goal will be difficult, since toll collection companies are often partly owned by local governments.