The size of the deal will be determined on Tuesday following the briefings with investors in Asia and Europe, two sources with direct knowledge of the matter said.

The term sheet showed the airline had appointed Citigroup as sole global coordinator, along with BofA Securities and HSBC as joint bookrunners for the issue.

"Singapore Airlines is looking to diversify funding. They did a few successful fund raisings previously. Coming out at this time is a smart strategy," said Ezien Hoo, Singapore-based credit research analyst at OCBC Bank.

Singapore Airlines has in the past carried out debt deals in Singapore dollars rather than US dollars.

The deal will not be offered to investors based in the United States, according to the term sheet.

"We can confirm that SIA did not have any USD issuance in the past," the airline said in an email response to Reuters.

SIA, which counts Singapore state investor Temasek Holdings as its biggest stake holder, has issued $2.77 billion in five bond issuances in the past seven years, according to Dealogic.

The most recent was a $372 million ten-year private placement deal in November.

The airline said in a statement Monday it expected its passenger levels by the end of March to be about 25% of its pre-COVID levels and it would fly to nearly 45% per cent of its pre-crisis destinations.

"In line with Singapore's progressive re-opening, as well as the gradual vaccination of the population across the world, we expect to see a measured expansion of the passenger network," it said.

There was $22.7 billion worth of US dollar debt issued last week in Asia, the busiest week in a year, Refinitiv data showed.

(Reporting by Scott Murdoch in Hong Kong and Anshuman Daga in Singapore; Editing by Simon Cameron-Moore)

By Scott Murdoch and Anshuman Daga