All the victims were in Wuhan, the capital of China's central Hubei province where the virus originated at its seafood market. The virus has been dubbed "Wuhan Virus" after the city.
Officials confirmed the new mystery virus, which has no cure, can spread between humans, and 15 medical staff in Wuhan have now been infected, prompting fears of a pandemic.
Concerns are growing as hundreds of millions of people in China are set to travel home, often from cities to the countryside, or travel abroad for the week-long Lunar New Year holiday which starts on Saturday.
The World Health Organisation (WHO) has called an emergency meeting for Wednesday to consider declaring an international health emergency, a move only used for the worst epidemics.
WHO spokesman Tarik Jasarevic warned: "More cases should be expected in other parts of China and possibly other countries in the coming days."
China's National Health Commission said 291 people have been infected in the country - mainly in Wuhan - since the virus emerged in mid-December, but reports are coming in all the time from different Chinese regions indicating the virus is spreading fast.
A study by Hong Kong University in collaboration with WHO estimated by Tuesday 1,343 people had been infected, along with 116 people in 20 other Chinese cities.
Thailand has also reported two cases, while South Korea, Japan and Taiwai have all reported one case, all people who had been to Wuhan.
Russia, Australia, Singapore, the US, Thailand, South Korea, Malaysia and Japan are among the countries increasing airport screenings.
One of the cases in Thailand was discovered after a woman was screened in Bangkok airport.
The virus has brought back bad memories from 2002-03, when Severe Acute Respiratory Syndrome (SARS), which belongs to the same family of coronaviruses as the new outbreak, killed nearly 800 people around the world after starting in China.
Doctors began seeing symptoms including fever, coughing and breathing difficulties in people who worked at or visited Wuhan's seafood market last month.
As the number of deaths and cases of the new virus increased, financial markets reacted, with China's onshore yuan falling 0.6%, its biggest daily drop since 26 August, 2019.
Airline and travel stocks across the region also fell.
