Norwegian Cruise Line rolled out plans for more sailings to Cuba despite ongoing uncertainty about whether US President Donald Trump will leave in place the sanctions easing of his predecessor.

The Miami cruiseship owner, the flagship brand of New York-listed Norwegian Cruise Line Holdings, said it will extend its weekly roundtrip sailings from Miami to the Caribbean island with 33 voyages in 2018.

The 2,000-berth Norwegian Sky (built 1999) will carry passengers on four-day cruises, all but one of which will include an overnight stay in Havana and call at private island Great Stirrup Cay in the Bahamas.

30 journeys in 2017

The ship will open the season in March of next year, after completing 30 calls in Cuba this year.

"Cuba is a spectacular destination and we are seeing incredible demand from our guests to experience the beautiful and cultural-rich city of Havana and her warm and friendly people," said chief executive Andy Stuart.

"We are excited to provide even more opportunities for our guests to experience this incredible destination into 2018."

Will US President Donald Trump say "you're fired!" to sanctions easing. Photo: White House

The Norwegian Sky will make its first call to Cuba this year, following sister line Oceania Cruises' first journey to the island on the 1,250-berth Marina (built 2011).

Closed to US cruise companies for more than 50 years until US President Barack Obama began easing sanctions against the country, Cuba is a hot destination for the cruise industry.

Cruise lines are reeling in premium prices for the cruises, and are pocketing more money off shore excursions.

But the Trump White House has been reviewing the policy towards Cuba after a campaign last year that saw the Republican candidate give mixed messages on his stance on sanctions easing.