Only a fraction of Australians in disability care residences have had a coronavirus vaccination despite being in a priority group.
A total of 1640 doses have been delivered out of 25,000 people in disability residential care.
Health department associate secretary Caroline Edwards conceded aged care residents had been prioritised.
"Disability facilities has been a much slower start than we would have liked. We're now turning our attention to that," she told a Senate inquiry on Tuesday.
Health department boss Brendan Murphy said he hoped to have all vulnerable Australians in phase 1a - including people at disability residential facilities - vaccinated by the middle of the year.
"We are ramping up disability as we speak and we are absolutely cognisant of getting them protected as soon as possible."
Professor Murphy said the risk of coronavirus had alleviated since last year because there was now no community transmission, but winter could pose a new challenge.
Officials have gone back to the drawing board for the vaccine rollout after the AstraZeneca jab was linked to rare blood clots.
The Pfizer jab is now the preferred vaccine for Australians under the age of 50.
Health officials have undertaken modelling which will be considered by national cabinet on Thursday.
Prof Murphy said national cabinet - made up of the prime minister and state leaders - would reach a clear policy position on the rollout.
The only direction so far is the advice on Pfizer being preferred for under 50s.
"The states are interpreting that in their own ways at the moment which is why we need to get the national cabinet to agreement on that," Prof Murphy said.
Health Minister Greg Hunt was cautious on Tuesday when asked about a new timetable, saying the rollout was accelerating.
About 1.7 million doses having been delivered so far nationally.
Deputy Labor leader Richard Marles said the coalition's complacency in focusing on just a handful of vaccine candidates risked Australia's economic recovery.
Meanwhile, a vaccinated border staffer in New Zealand has tested positive for coronavirus just one day after the start of a two-way travel bubble with Australia.
Mr Hunt said Australian authorities had full confidence in New Zealand's containment system.
Australian Associated Press