United States biotech firm Moderna has said it was seeking clearance with regulators around the world to put 50 per cent more coronavirus vaccine into each of its vials as a way to quickly boost current supply levels.

The company issued a statement after The New York Times first reported the US Food and Drug Administration had already cleared it to increase levels by 40oc.

"In order to better maximise resources as well as maximise opportunities to deliver more doses into each market faster, Moderna has proposed filling vials with up to 15 doses of vaccine versus the previous 10 doses," a spokesperson said in a statement to AFP.

"Any resulting change would be subject to final approval from the various regulatory authorities. Implementation of any such changes would be expected to be completed in approximately a two- to three-month period," he said.