Shipping operations across the US Southeast are shutting down as Hurricane Irma churns in the Atlantic basin.

The hurricane, one of the most powerful ever recorded, was passing over Puerto Rico and the US Virgin Islands by Wednesday afternoon. The US National Weather Service said the storm is "potentially catastrophic" and one of the five strongest ever recorded in the Atlantic.

Passengerships in the region have seen the first effects.

UBS analyst Robin Farley says Carnival Corp and Royal Caribbean Lines cancelled two cruises each so far due to Irma.

Norwegian Cruise Lines also cancelled two sailings, with an additional two ending earlier.

The interruptions will impact the companies' bottom lines, she added. Carnival and Royal Caribbean may see earnings per share shaved by $0.01 or so in the current quarter. Norwegian Cruise Lines may see earnings take a $0.05 hit.

A TOTE Maritime-owned containership, the 3,100-teu Perla Del Caribe (built 2016) is headed away from the storm's path to Jacksonville, Florida. Another ship, the 3,100-teu Isla Bella (built 2015) is also headed away from Irma's path.

A TOTE spokesperson said that the vessel movements are the result of US Coast Guard advisories for Puerto Rico and Florida ports advising ships to depart before the storm hits.

"Our crews are trained to deal with unfolding weather situations and are prepared to respond to emerging situations while at sea.

"TOTE Services has great confidence in its highly experienced officers and they are currently adjusting their sailing schedules accordingly," according to a statement from the company.

Port Everglades, a container and cruise ship terminal at the tip of Florida, remains open for now. But it says the US Coast Guard may issue a warning by Friday that gale force winds are soon expected and that ships in the area make final mooring arrangements.

Irma also has the potential to disrupt Caribbean basin energy trades due to the high number of storage terminals located throughout the region, says shipping analyst Court Smith.

St Croix, in the US Virgin Islands, has 32 million barrels of storage for crude and other oil products.