The number of new coronavirus infections inside China was for the first time overtaken by fresh cases elsewhere on Wednesday, with Italy and Iran emerging as new epicenters of the rapidly spreading flu-like virus.

U.S. health authorities, having confirmed 59 cases so far, warned that a pandemic is likely.

"Concerns surrounding the latest development of coronavirus continue to dominate the market, which is expected to stay choppy to any latest development of the outbreak," Mizuho Bank said in a note to clients.Leading losses in the region, Indonesian shares fell up to 2.5% and were on track for a fifth session of losses.

The index was dragged lower by losses in financial stocks, with Bank Rakyat Indonesia slumping 6%, while Bank Central Asia slipped nearly 2%.

Singapore shares were headed for their worst week since last August, with financials being the biggest laggards.

Heavyweights Capitaland Ltd and DBS Group Holdings shed 1.63% and 0.53%, respectively.

Thai shares flitted between positive and negative territory for most of the session, while the Vietnamese index dropped to its lowest in more than a year.

Bucking the sombre mood, the Malaysian bourse gained 0.3%, with Public Bank Bhd and Hong Leong Bank Bhd climbing 0.5% and 2.2% after both lenders reported higher quarterly numbers on Wednesday.

"The gain was aided by a potential resolution to the political impasse and an economic stimulus expected to be unveiled today," said Imran Yusof, a senior analyst with MIDF Research.

"The idea is that the stimulus will be enough to arrest the economic happenings that Malaysia is facing at the moment," Yusof added.

(Reporting by A K Pranav; Editing by Sherry Jacob-Phillips)