The measure applies on Singapore citizens and permanent residents (PRs) too, a Channel News Asia report said.
Previously only long-term pass holders and short-term pass visitors entering Singapore were required to present a negative COVID-19 polymerase chain reaction (PCR) test report.
The new directions have come after the Ministry of Health announced last week that Singaporeans and PRs are now required to present a report of the test, taken within 72 hours before departing for Singapore.
"Airlines must not allow a passenger to board the flight to Singapore if that passenger fails to produce the result of the required PCR test or if the result of that PCR test is positive. They will be responsible to carry a person who is denied entry into Singapore back to the point of departure, said Margaret Tan, Security Director at the Civil Aviation Authority of Singapore.