BUSINESSDESK: Cook Strait ferry operators are unwilling to sign up to the idea of a new terminal south of Blenheim until they see the charges and one says running ferries again from Wellington to Lyttelton should be looked at.

The government is assembling a team led by Treasury and transport officials to further investigate building a $422 million inter-island road and rail freight port at Clifford Bay, Transport Minister Gerry Brownlee said today.

"Cabinet believes the business case we've been presented is strong enough to justify further testing the viability of this major change to New Zealand's transport infrastructure," he says in a statement.

KiwiRail chief executive Jim Quinn told BusinessDesk after the KiwiRail annual meeting last week that the Clifford Bay ferry terminal was a government decision.

"If a decision is made to build it they will come and talk to us. If it isn't commercial we won't be signing up. I don't mean that as a threat," he said.

Strait Shipping managing director Sheryl Ellison was eager to understand the business case for the new terminal.

"Unlike our competitor, we have no idea of the basics such as indicative port fees and other costs, and as a result we're not able to determine whether or not it would be feasible for Strait Shipping to go to Clifford Bay," says the operator of Bluebridge ferries, with 40% of the Cook Strait freight market.

Ms Ellison asked if the government had looked at placing ferry facilities at Lyttelton Port, which serves Christchurch.

She says 75% of interisland freight goes to Christchurch and beyond, and the rail line down the coast to Christchurch was expensive to maintain.

"Facilities at Lyttelton Port are also an option worth investigating."

Ferry services between Wellington and Lyttelton ended in 1976 after operating for more than 80 years. The end of the service was blamed on cheaper air travel, which reduced passenger demand.