TT-Line executives and Infrastructure Minister Rene Hidding were grilled by the state opposition parties on the final day of government business enterprise hearings on Friday on the plan to replace the ships.

Mr Hidding said a cabinet sub-committee was established last year to look at funding requirements and port pairing for the new vessels, adding that there was $80 million in the bank already.

But Greens leader Cassy O’Connor said this only represented about 10 per cent of the overall cost, using Mr Hidding’s earlier estimate of $300 million euros – or $427 million when converted to Australian dollars today.

TT-Line chairman Michael Grainger said the vessels’ cost would depend on design, country of origin, and capacity, however.

“(The cost) will depend on the global economy and the shipbuilder. That could mean the difference of tens of millions of dollars.”

Labor’s Scott Bacon accused Mr Hidding of not knowing where the vessel replacement money was kept when he could not definitely say if it was being held in the government’s consolidated revenue fund.

“You are taking $80 million for vessel replacement and it’s really being used to prop up the budget,” Mr Bacon said.

Mr Hidding denied this was the case and said a specific vessel replacement fund would be set up.

He said vessel costs would be reflected in the forward estimates of future budgets.

“They are going to be funded through a mix of company funding and probably an investment by the government,” Mr Hidding said.

He said TT-Line was projected to have $130 million in cash by 2020.

Mr Hidding said a $18.8 million profit last financial year put them in a position to pay two dividends to be locked away for vessel replacement.