Atlanta: The US Department of Homeland Security warned that flights could be re-routed for coronavirus screening if it's discovered mid-flight that a passenger has been to China recently.

The US and US Department of Homeland Security flags fly in Karnes City, Texas. Credit:AP

That could affect travellers who have not been to China, if someone on their flight has been in China in the last 14 days, according to the agency.

Homeland Security also warned that travellers who show symptoms "should be prepared for the possibility of prolonged delay to avoid spreading the infection".

"We realise this could provide added stress and prolong travel times for some individuals, however public health and security experts agree these measures are necessary to contain the virus and protect the American people," Department of Homeland Security acting secretary Chad Wolf said in a written statement.