An international supplier of marine fuel has joined the growing list of vendors who say that Nova Star Cruises owes them money, bringing the total sum of claims to $2.6 million.

Cockett Marine Oil filed a notice Thursday in U.S. District Court in Portland that the ferry service owes it more than $1 million for fuel delivered from Aug. 31 to Oct. 31. The Dubai-based company is asking the court to order the ship be sold at auction so it can get paid.

Also on Thursday, McAllister Towing and Transportation Co. filed notice claiming it has $12,000 in unpaid invoices for tugboat services it provided the Nova Star.

The two new claimants indicate the Nova Star ended its 2015 season with at least $2.6 million in unpaid bills.

The ferry, which transported passengers for two seasons between Portland and Yarmouth, Nova Scotia, remains in Portland Harbor while creditors line up in court seeking payment for services rendered to its operator, Nova Star Cruises.

Magistrate Judge John H. Rich III, who two weeks ago directed the U.S. Marshals Service to “arrest” the ship and formally take possession of it, must determine the validity of the claims and decide who gets paid first.

If Nova Star Cruises doesn’t have the cash, Rich could order the ship to be sold at auction. Nova Star Cruises leased the ship from Singapore Technologies Marine, which built the $179 million ship in 2010.

Under maritime law, the owner’s interest is subordinate to those with valid liens. If the ship is sold at auction, Singapore Technologies would get whatever money is left over after all the bills are paid.

“The law provides a process to adjudicate everybody’s claim,” said Andrew Helman, an attorney for Cockett Marine Oil and McAllister Towing.

Mark Usinger, who runs A.L. Griffin Ship Chandlers in South Portland and is claiming $13,000 in unpaid bills for supplies and parts it purchased for the Nova Star, said the ship is a valuable asset that could be producing revenues for a different owner if it was allowed to go free.

“If I had to guess, I would think the owners in Singapore are scrambling behind the scenes to come up with the money to pay the bills so they don’t lose the ship at a bankruptcy auction,” he said.

Other creditors include the city-owned Portland Development Corp., which says the ferry operator owes it more than $151,000 for a loan it extended last year for modifications to the Nova Star. The operator also owes the city $85,000 for use of municipal facilities when it tied up in the harbor.

Also making claims are World Fuel Services, which says it is owed $491,000; Vessel Services Inc. claims $483,000 in unpaid bills; Sprague Operating Resources has submitted a lien for $147,000; and Brown Ship Services says it is owed $48,000. The Portland Pilots started the legal process two weeks ago when it filed documents claiming it is owed more than $195,000.

Nova Star Cruises has received millions in subsidies from the Nova Scotia government to operate the service, deemed crucial to the province’s tourism industry. On Oct. 20, the provincial government gave Nova Star Cruises $1.5 million, its final payment for the season. The money is the last installment of nearly $10 million ($13 million Canadian) the government promised for Nova Star’s 2015 sailing season.

The Nova Star for two weeks has been anchored in Portland Harbor with a small crew on board. The ship on Thursday was docked at the Ocean Gateway terminal because of high winds.

Dennis Bailey, a spokesman for Nova Star Cruises, did not respond to a phone call or email inquiry. The company president and CEO, Mark Amundsen of Eliot, could not be reached for comment.