In a letter to Sitharaman, he said: "The duty if imposed, it would escalate the cost of solar power by about 100 per cent."
He said the indigenous manufacturers can be compensated with appropriate subsidy.
"I have a firm view that the indigenous solar cell industry, which is in nascent state, needs protection and nurturing," Gadkari added.
The Commerce Ministry last month had recommended levying anti-dumping duty on solar cells imported from the US, Malaysia, China and Chinese Taipei.
The levy would be applicable on solar modules and cells assembled partially or fully, originating in or exported from these countries.