There is "no sign" of a larger hantavirus outbreak after the evacuation of the last passengers from a disease-stricken cruise ship, the head of the UN health agency has said.

But the World Health Organisation's chief Tedros Adhanom Ghebreyesus warned "the situation could change" and there could still be more confirmed virus cases.

The MV Hondius left Spain's Tenerife island on Monday and is sailing to the Dutch port of Rotterdam. Two flights with the final group of 28 passengers landed in nearby Eindhoven on Tuesday.

Three people have died after travelling on the ship. An American and a French national who previously returned home have tested positive. Overall, seven cases have been confirmed.

Twelve employees at a Dutch hospital are now in quarantine over possible exposure to the virus after treating one of the evacuated passengers.

The hospital in the city of Nijmegen said on Monday this was a precautionary measure, as the workers did not follow strict protocols while handling the patient's blood and urine samples.

At Tuesday's press conference in Madrid, Ghebreyesus said: "At the moment, there is no sign that we are seeing the start of a larger outbreak.

"But of course the situation could change and, given the long incubation period of the virus, it's possible we might see more cases in the coming weeks."

And he stressed that "our work is not over" to contain the outbreak from the cruise ship.

Symptoms can include fever, extreme fatigue, muscle aches, stomach pain, vomiting, diarrhoea and shortness of breath.

WHO officials previously said the risk of a major outbreak is very low.

The Dutch-flagged vessel is expected to take six days to sail to Rotterdam and provisionally arrive on the evening of 17 May. Exact procedures upon arrival remain under discussion, the ship's operator Oceanwide Expedition said, but the vessel will undergo sanitation.

The final six passengers - four Australians, one Briton and one New Zealander - and some crew members left the ship on Monday.

Overall, 122 passengers and crew of the MV Hondius have been repatriated to the Netherlands and their home countries on government-chartered flights over the past few days.

As of Monday evening, Oceanwide Expeditions said 27 people remained on board the ship - 25 crew members and two medical staff.

These included 17 people from the Philippines, four from the Netherlands (including the two medical staff), four from Ukraine, one from Russia and one from Poland.

Ukraine's foreign ministry said the Ukrainians on board would help with the ship's transfer to the Netherlands and would quarantine at a medical facility on arrival. It added that they had shown no signs of illness.

Seventeen Filipino crew members arrived in the Netherlands on Tuesday morning, according to the Philippine Embassy.

Spain's health ministry earlier said one Spaniard who is quarantining in Madrid after being evacuated from the vessel had also provisionally tested positive for hantavirus on Monday.

French Health Minister Stéphanie Rist said a woman was isolating in Paris and that her health was deteriorating, with 22 contacts being traced.

In a separate development, the US health department said a second American national on Sunday's repatriation flight had also shown mild symptoms, adding that both passengers had travelled back in "biocontainment units out of an abundance of caution".

Two British nationals with confirmed cases are currently being treated in the Netherlands and South Africa.

An elderly Dutch man was the first passenger who died on board the MV Hondius on 11 April. He had earlier developed symptoms and is believed to have been the first infected in the outbreak, but died before he could be tested.

His wife left the ship on 24 April on the island of St Helena and flew to South Africa. She died two days later in a clinic in Johannesburg.

A German woman died on board the cruise ship on 2 May.

Both women were confirmed cases.

The MV Hondius had been carrying 147 passengers and crew from 23 countries after departing from Ushuaia in Argentina on 1 April.