Transport Minister Michael Ferguson told a government business enterprise scrutiny hearing on Friday the offer put to TT-Line by VicPorts was quite unacceptable in terms of pricing and conditions.

"I'm not in a position to provide numbers as they are subject to a negotiation," Mr Ferguson said.

"What we won't be able to accept is unreasonable price charges that affect our business and affect business and passenger costs."

Mr Ferguson did not name other ports which may be considered but said it was well-known there were other ports in the vicinity.

TT-Line chief executive Mike Grainger said the lease negotiation was ongoing.

"We have a lease until 2022 so it's not something that is immediate today or tomorrow," Mr Grainger said.

The committee heard two new Spirit of Tasmania vessels were on track to be delivered by March 2021 despite the contracted shipbuilder Flensburger Schiffbau-Gesellschaft experiencing financial difficulties.

"The company continues to be continually interacting with FSG regarding construction contracts," Mr Ferguson said.

"TT-Line has been in contact with the other shipbuilders shortlisted should FSG not be able to fulfill its contract."

Mr Grainger said FSG has not advised they intend to break their contract.

"We don't really know what their financial situation is - we're just reading the media reports," Mr Grainger said.

"We've taken some legal advice from our lawyers in London on those unsubstantiated reports just so we can be across their situation as best we can.

"We won't pay any money until we can have that assurance that money can be fully refunded in the event of breach of contract."

Mr Grainger declined to tell the committee the date the first payment would be made because this was part of a commercial in confidence contract.

He was unable to say when the ships would begin construction citing this as a matter for the shipyard.

McIntyre independent MLC Tania Rattray questioned at what point TT-Line would stop waiting for a refund guarantee from FSG and the Spirits would need to built elsewhere in order to be delivered on time.

Mr Grainger said there were trigger dates in the contract which determined this.

TT-Line chief executive officer Bernard Dwyer said the new vessels would be able to dock at Station Pier as is but additional infrastructure was needed to maximise their efficiency.

"There will be additional infrastructure needed to they can load and unload per their design," Mr Dwyer said.

Mr Dwyer said one of the biggest advantages of the new design was the ability to have three level loading instead of two.

"Three level loading and discharge allows us to separate passenger vehicles from freight," he said.

Mr Dwyer said the design of the new vessels would also allow pet owners access to the pet area through the whole journey and pet friendly cabins would be available in the longer-term.