Authorities in Spain have granted permission for a Netherlands-flagged luxury cruise ship hit by a deadly hantavirus outbreak and anchored off Cape Verde to sail to the Canary Islands.

In a statement late on Tuesday, Spain's Health Ministry said the World Health Organization had explained that Cape Verde, in West Africa, could not receive the 147 passengers and crew of the MV Hondius.

"The Canary Islands are the closest location with the necessary capabilities," the ministry said. "Spain has a moral and legal obligation to assist these people, among whom are also several Spanish citizens."

Arrival in the Canary Islands was expected in "three to four days", it said, without specifying the port.

"Once there, the crew and passengers will be duly examined, cared for, and transferred to their respective countries," it said.

Since departing Argentina about a month ago for an Atlantic Ocean crossing, three passengers have died.

The WHO is investigating how hantavirus appeared on the ship, noting that the first victim developed symptoms on April 6 and possibly contracted the virus before boarding.

The rare disease, typically transmitted from infected rodents via urine, droppings or saliva, was suspected in the deaths of the three passengers. The WHO has said it had been told that "there are no rats on board" the ship.

As additional cases emerged, passengers and crew were placed in isolation after Cape Verde authorities barred the ship from docking. The vessel is anchored just off Praia, the island nation's capital.

WHO Director-General Tedros Adhanom Ghebreyesus said three patients with suspected hantavirus infections have been evacuated from the ship and are on their way to the Netherlands.

After the evacuations, the ship would "continue its route", said Ann Lindstrand, the WHO representative in Cape Verde.

Oceanwide Expeditions, the operator, confirmed it plans to send the ship north to the Canary Islands, either Gran Canaria or Tenerife.

Passengers told The Associated Press that they were coping well with the isolation.

"Our days have been close to normal, just waiting for authorities to find a solution," said Qasem Elhato, 31. "But morale on the ship is high and we're keeping ourselves busy with reading, watching movies, having hot drinks and that kind of things."