The Andrews government has refused to release independent assessments of a controversial new toll road scheme likely to deliver road giant and CityLink operator Transurban tens of billions of dollars in toll windfalls.

In December the government released a business case for the $5.5 billion Western Distributor, a new road linking western Melbourne to the central city, proposed by Transurban under the government's market-led infrastructure proposal policy.

The business case was released with fanfare, the government seeking to contrast itself with the Napthine government's refusal to release the business case for its contentious East West link.

However, the crucial financial data that would allow Victorians to make their own assessment of the Western Distributor deal have been redacted from the Andrews government document.

The government also refused to release two reports on the Western Distributor business case by a panel of independent infrastructure experts, Kerry Schott and Tony Canavan​.