* Australian no-travel warning at unprecedented level
* Concerns grows about faster coronavirus transmission
* Government unveils aid package for airlines (Recasts and updates throughout with more detail, comment)
By Swati Pandey
SYDNEY, March 18 (Reuters) - Australian Prime Minister Scott Morrison on Wednesday said the country's citizens should abandon all overseas travel because of the coronavirus epidemic and banned all non-essential indoor gatherings of more than 100 people.
Morrison upgraded the official travel advice for Australians thinking of heading overseas to an unprecedented "Level 4: Do not travel" for the entire world.
"The travel advice to every Australian is 'Do not travel abroad. Do not go overseas," Morrison said during a televised news conference. "That is the first time that has ever happened in Australia's history."
Anybody who travels during a Level 4 ban is warned that the Australian government may not be able to assist if they get into trouble while abroad, according the government's official SmartTraveller website. It also recommends people already in a "do not travel" area consider leaving.
Australia has recorded around 425 infections and five deaths, but officials are growing increasingly concerned about the prospect of exponential rise in cases.
Morrison said schools would remain open, citing expert health guidance, and reiterated the need for social distancing and good hand hygiene to curb the spread of the virus.
The travel bans and other restrictions have crippled Australia's travel, tourism, retail and entertainment sectors.
Economists are predicting the country will slip into its first recession in nearly three decades in the first half of 2020.
The government unveiled an aid package for hard hit airlines on Wednesday, including waivers on domestic air traffic control fees.
Morrison has already flagged a stimulus package worth around A$17 billion ($10.2 billion) and said on Wednesday the government was "considering quite extensively further economic measures" to dull the impact on the economy.
The Reserve Bank of Australia this week pumped liquidity into money markets and has promised further stimulus measures will be announced on Thursday.
"This is a once in a hundred year type event," Morrison said. "We are going to keep Australia running. We are going to keep Australia functioning. It won't look like it normally does." ($1 = 1.6706 Australian dollars) (Reporting by Swati Pandey; Editing by Tom Hogue and Jane Wardell)
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