New figures show almost a quarter of all available doses of the COVID-19 vaccines are not being used.
The federal health department on Monday released data comparing the availability of vaccine doses and the number of jabs delivered.
Nationally, dose utilisation as of week 12 of the vaccine rollout was 77 per cent.
The Northern Territory had the worst lag of all the jurisdictions, with 47,652 doses available and 22,953 administered, giving it a utilisation rate of just 58 per cent.
Queensland was the worst performing state, with 317,810 doses available and 170,330 delivered - or a usage rate of 64 per cent.
Across the other states and territories rates were: Tasmania (90 per cent), NSW (78 per cent), Victoria (77 per cent), WA (80 per cent), SA (79 per cent), ACT (82 per cent).
The health department found all doses available for the aged and disability care program were being used, while the commonwealth primary care program was at 75 per cent utilisation.
So far, 3.1 million doses have been administered nationally.
Health Minister Greg Hunt said some adjustments may be needed in the states and territories.
"We are encouraging all the states and territories - who we believe are doing an excellent job - to continue to use their vaccines," he told reporters in Melbourne.
"And where they feel that they have more capacity to open up channels, or where they feel they are using their capacity, to adjust their ordering."
Commodore Eric Young from the Vaccine Operations Centre said utilisation rates had dropped when the vaccine program was "recalibrated".
But the rates were now improving, he said.
