Spanish health ministry officials were on Thursday investigating the country's first suspected cases of locally-transmitted coronavirus infections, with one elderly patient in a serious condition.

Three people are in hospital—two in Madrid and one in Seville—with the flu-like disease.

None had travelled to a hotspot country, nor had any connection to a known patient, said Fernando Simon, the ministry's chief coordinator for health emergencies.

"Their possible ties with cases outside of Spain, or imported cases are being investigated," he told a news conference.

Since the start of the epidemic, Spain has registered 17 cases of coronavirus infection, 15 of which were detected since Monday evening.

Of that number, 12 cases involve Italian nationals or people who had been in Italy, the worst-hit country in Europe where more than 525 people have been infected and 12 have died.

Four Italian tourists tested positive on Tenerife in the Canary Islands with authorities imposing a quarantine on the hotel where they were staying with more than 700 other guests.

But the quarantine was partially lifted on Thursday, with staff and around 130 tourists allowed to leave after testing negative, officials said.

If confirmed that the disease is now spreading from person-to-person within Spain, the government would have to take extra measures to prevent further contagions, such as "reducing large gatherings", Simon said.

One of the two Madrid patients is a 77-year-old man is seriously ill and in intensive care, Madrid's regional government said. The other is a 50-year-old man in stable condition.

The first suspected case of local transmission was discovered on Wednesday in a 62-year-old man in the southern region of Andalusia who is in isolation at a Seville hospital.

"The fact that it has not been possible to determine where he became infected means the virus may have circulated for a while in Andalusia," Simon told radio Onda Cero earlier on Thursday.

Among the latest diagnosed with the infection was a sports journalist from the coastal city of Valencia who went to Milan to cover the February 19 Champions League clash between Valencia and Atalanta Bergame.

"Coronavirus has recruited me," joked reporter Kike Mateu, wearing a mask in a video sent from his hospital bed.