CB Port director Stephen Grice said a ferry could do the 74km journey from Wellington to Clifford Bay in about two hours, taking less time than the 104km route from Wellington through the Marlborough Sounds to Picton.
He said the company met with Rail Minister Winston Peters in June, who subsequently committed to Picton but was open to more information, Grice said.
"The minister's welcomed us to do a market-led proposal so that we can go through the validation process ... and the two proposals can then be compared on their merits, side by side."
Grice said the initial design of the terminal would allow for rail-enabled ferries, which would entail discussions with the Government on how that part could be funded.
However, it was possible the terminal could be entirely privately financed.
The group has submitted the plan to the Government investment agency, National Infrastructure Funding and Financing.
It is not the first time Clifford Bay has been considered - and then discarded - as a possible alternative port.
In 2013, the Government looked at the business case for a new terminal at Clifford Bay. Then-transport minister Gerry Brownlee said a report showed an upgrade of the Picton terminal would be significantly more cost-effective.
