A Melbourne woman in her 20s who flew to Australia from China last Saturday has been announced as the fourth confirmed case of coronavirus in Victoria.

The Health Department has issued a statement saying the woman had spent time in the city of Wuhan and flew back to Australia on January 25.

Wuhan, a city of 11 million and the capital of China's Hubei Province, is the epicentre of the outbreak, and has been locked down by Chinese authorities for more than a week in an effort to stop the disease from spreading.

The woman fell ill two days after arriving in Melbourne. She was seen by doctors at a Melbourne hospital on Thursday, and has been in isolated at her home since then.