AUGUSTA — Gov. Paul LePage is officially throwing his weight behind the only Maine-based company currently competing for a contract to restart ferry service between Maine and Nova Scotia.

On Tuesday, LePage sent a letter to Nova Scotia Premier Darrell Dexter to publicly back Eliot, Maine-based Quest Navigation’s proposal to restart the ferry service, which was lost in 2009 when Bay Ferries Ltd. ceased operating its high-speed ferry, The Cat, because of tough economic conditions.

LePage also revealed in his letter that the state would offer the company marketing and financial-related assistance.

Dexter last September committed to providing $21 million in subsidies over seven years to help an operator restart the service between Yarmouth, Nova Scotia, and a port in New England.

Three companies at the beginning of July submitted proposals to restart the service. Quest Navigation partnered with Singapore-based shipbuilder ST Marine Ltd. to form STM Quest Inc. as an operating company to bid on the contract. The other two companies competing for the contract are Miami-based Balearia Caribbean Ltd., which is owned by a Spanish shipping company, and Dover, England-based P&O Ferries.

“I understand that there are many factors that your team will need to consider in selecting the proponent that best meets the needs of the service,” LePage wrote to Dexter. “However, I would like to take this opportunity to formally declare my support for this proposal and to confirm that the state of Maine will offer the following assistance to STM Quest.”

According to his letter, the state will “work with the Quest Navigation marketing team and we will allocate a portion of our marketing to promote the ferry service.”

Maine will also “assist” the company in securing a $5 million operating line of credit and potentially help with any infrastructure expenses related to fitting ferry operations into Portland’s working waterfront, according to the letter.

“It means a lot to have the backing of Governor LePage,” said Mark Amundsen, president of STM Quest Inc., in a statement provided to the Bangor Daily News. “Clearly, he understands the huge value that our ferry service means for tourism, jobs and economic development in Maine and Nova Scotia. We are very grateful for his support.

“The province of Nova Scotia is still conducting its evaluation and, until the process is concluded, we’d prefer not to make any further comment,” Amundsen said.

STM Quest already has the ship lined up that would provide the ferry service. The ship, to be christened the Nova Star, is 161 meters long, can carry 1,215 passengers and was originally built to ferry passengers and vehicles across the English Channel.

Adrienne Bennett, the governor’s spokeswoman, said the governor is publicly supporting STM Quest because it has been open about the fact its service would be between Portland and Yarmouth, Nova Scotia. However, the governor would be open to working with either of the other companies if they committed to using Portland as their New England port.

“The significance of this particular bid is it’s the only one that identifies Portland as a port of call,” Bennett told the BDN on Friday. “We see that as a huge economic advantage. If another company were to commit to Portland, we are very willing and happy to have those discussions.”

While the other two companies competing for the contract have been silent on the details of their projects, a spokesman for P&O Ferries did tell the BDN earlier this month that a Portland-Yarmouth, N.S., route “is what we have in mind.”

Concerning the proffered marketing assistance, “we wouldn’t be cutting the company a check per se,” Bennett said. “What we would want to do is incorporate them into our marketing strategy, the branding effort and attraction of tourists and businesses to our state.”

In addition, the Maine Department of Economic and Community Development would be able to work with private and quasi-public institutions like the Finance Authority of Maine to secure capital for the company, Bennett said.

“We would be assisting them in that process, and making it as streamlined a process as possible,” she said.

Bennett said the governor is very interested in the possibility of incorporating freight service into the mix, and that the Nova Star would have the capacity to do that.

Approximately $19 million of the nearly $100 million transportation bond package LePage proposed in March is designated for investments in port and marine infrastructure, and could be used if need be to upgrade Portland’s waterfront to handle restarted ferry operations, Bennett said.

“That could be vital to help us move forward with this project, but obviously that hasn’t come out yet,” she said, referring to the fact that the Legislature did not approve the bond package before adjourning earlier this month. The $6.5 million in port-related bond funding that was approved by voters in 2012, however, is already designated for other uses and could not be used for the Portland waterfront, she said.

This is the second request Nova Scotia has made for proposals to restart the service. The first request was last fall and only garnered two submissions — one from Quest and the other from Baltimore-based engineering firm Maritime Applied Physics Corp., which has an office in Brunswick. In March, the province said neither proposal met the province’s minimum criteria and it launched a new procurement process.

Quest’s first proposal involved a partnership with Maritime Holdings Group, a Florida-based ferry operator that operates ferries in the Caribbean. According to the statement on the Nova Star website, it appears Maritime Holdings Group no longer is involved with the proposal.

“I’m personally excited about the prospect of seeing the ferry service return, and I am pleased to offer the support of the state of Maine,” LePage wrote.