Health authorities in Singapore on Friday urged people not to shake hands as a measure against the spread of the new coronavirus in the Southeast Asian city-state.

The warning comes amid a rise in the number of new infections not linked to recent travel in China or previous cases.

"As a general good practice, we advise people not to shake hands during this period, but adopt alternative greetings," the Health Ministry said in a statement, urging Singaporeans to be prepared for "widespread community transmission."

The advice is part of additional measures announced by the ministry as it upgraded its risk assessment from yellow to orange under its "Disease Outbreak Response System Condition."

Orange is the second-highest level in the four-level color-coded framework.

Other measures include the cancellation or postponement of large-scale public events being planned at this time and urging companies to take the temperatures of employees twice a day.

However, the Singapore Airshow, one of the world's top three airshows, will go ahead as planned next week. A Hindu festival called Thaipusam will also take place Saturday but with precautionary measures such as temperature checks.

The government reported three new cases of coronavirus on Friday, raising the total number of local infections to 33, the second-highest number outside China after Japan.

Two of the previous cases are in critical condition.

The number of people infected with the virus has reached over 31,000 in mainland China, with 636 confirmed deaths, the Chinese government said Friday.