The ferry is carrying an average of 100 people per trip but the company says bookings have picked up.

Officials in Nova Scotia said Friday that they aren’t worried about the slow start for the ferry between the province and Portland, which carried only about 100 passengers per trip in the service’s first weeks.

They said it will take time to build business and they expect ridership to increase as the weather warms and people take vacations.

“We’re coming into the peak sailing season. That should generate more revenue,” said Toby Koffman, spokesman for the Nova Scotia Department of Economic and Rural Development Tourism.

The province has already spent $19 million in subsidies and loans for the service, which many Nova Scotians hope will lure American tourists to the province and boost its economy.

From the start of the service on May 15 through the end of the month, the Nova Star ferry sailed between Portland and Yarmouth, Nova Scotia, 29 times and carried a total of 2,924 passengers, for an average of 101 passengers per trip. The ship has capacity for 1,215 passengers. The ferry also carried 788 cars and 58 trucks in the second half of May, for an average of 27 cars and two trucks per trip.

The ferry’s operator, Nova Star Cruises, has told the province that it expects about 100,000 passengers this season, which ends Oct. 31. The ship burns about $40,000 worth of fuel per day and operates with a crew of about 120 people.

The Portland Press Herald obtained the ridership numbers Friday from Portland City Hall. Under its lease to use the city-owned Ocean Gateway terminal, Nova Star Cruises must pay Portland $2.50 per passenger, $3 per car and $20 per commercial truck transported by the ferry.

In all, the ferry company paid the city $10,834 in fees this month, based on the volume of passengers and vehicles from May 15 to May 31. The company is required to pay the fee on the 15th of each month after it reports its numbers.

While Maine has not provided any money for the new ferry service, that may change. The Finance Authority of Maine, a quasi-state agency, is working with an unidentified Maine bank to help Nova Star Cruises obtain a $5 million line of credit. The agency could guarantee all or a portion of the loan.

State officials say the ferry benefits the state because it brings tourists here.

Dennis Bailey, a spokesman for Nova Star Cruises, said the slow start was anticipated because the company wasn’t allowed to market its service or sell tickets until late March, when it obtained a required federal permit.

The company also missed deadlines to win business this year with major bus tour companies, which typically book their tours a year in advance.

Bailey said this cool, rainy spring also hampered business, but that has turned around this week with the arrival of sunny weather and summer vacation season. He said advance passenger bookings have “spiked way up” to more than 1,000 per day for the past week.

Critics say the ferry, which has many of the same amenities as a cruise ship, is too expensive to ride. A couple traveling during the peak season with a car and a cabin will pay $1,115 for a round trip on the ferry, which takes 10 hours to cross the Gulf of Maine.

To reach budget-conscious customers, the company began selling several promotional packages Friday with savings of 25 percent to 40 percent off its regular fares.

The company also has begun marketing the service as a convenient and cost-effective option for commercial trucking companies.

Nova Star Cruises opened its Maine headquarters this week in an office on Merrill’s Wharf on Portland’s waterfront. It also has an office in Bedford, Nova Scotia, a suburb of Halifax, and operates a call center in Yarmouth.

Jeff Monroe, a former port director for Portland, said the passenger and vehicle counts for the Nova Star in May were much lower than the numbers for May for the Scotia Prince, a cruise ferry that sailed between Portland and Yarmouth from 1982 to 2004.

On a slow day in May, the Scotia Prince would carry 70 to 80 cars, Monroe said, and about 500 passengers. That service carried as many as 150,000 passengers a year at its peak, in the late 1990s.

The link between Portland and Yarmouth ended in 2009, after Nova Scotia’s government refused to continue subsidizing the Cat, the high-speed ferry that succeeded the Scotia Prince.

Since then, travelers have changed their routines and learned to live without the ferry connection, Monroe said.

“There is absolutely no question that whenever you have a hiatus like that, you are going to lose business,” he said. “It takes a while to rebuild the market.”