Chinese travelers wear protective masks as they arrive to board trains at Beijing Railway station before the annual Spring Festival on January 21, 2020 in Beijing, China.

The toll from a new virus in China rose to six deaths and more than 300 cases on Tuesday as millions of Chinese prepared to travel for the Lunar New Year, heightening contagion risks.

Many in China scrambled to buy face masks to protect themselves from the previously unknown, flu-like coronavirus infection and airports around the world tightened screening.

The outbreak, which began in the central Chinese city of Wuhan, also worried financial markets as investors recalled the economic damage from China's Severe Acute Respiratory Syndrome (SARS) epidemic in 2002/2003 that it initially covered up.

The SARS coronavirus outbreak killed nearly 800 people then.

"We'll stay at home during the holiday. I'm scared as I remember SARS very well," said Zhang Xinyuan, who had been bound from Beijing for the Thai resort of Phuket before she and her husband decided to cancel their air tickets.

Authorities have confirmed more than 300 cases of the new coronavirus in China, mostly in Wuhan, a provincial capital and transportation hub, where it may have come from a seafood market.

Symptoms include fever, coughing and difficulty in breathing, and the viral infection can cause pneumonia.

Wuhan mayor Zhou Xianwang told Chinese state television on Tuesday six people had died in his city. The disease was spreading further around other parts of China, however, including five cases in the national capital Beijing.

Fifteen medical personnel are among those infected.

Abroad, Thailand has reported two cases and South Korea one, all involving Chinese from Wuhan. Japan and Taiwan also confirmed one case each, both nationals who had been to Wuhan.

The World Health Organization (WHO) will hold a meeting on Wednesday to consider whether the outbreak is an international public health emergency.