Health officials have promised to ramp up coronavirus jabs in disability care after revealing only a fraction have been administered in the high-priority group.

Federal Health Minister Greg Hunt has defended the delayed coronavirus vaccine rollout to disability care, despite senior officials conceding it is behind schedule.

The Morrison government is battling multiple fronts over its troubled rollout, which is now under fire over priorities and dose locations.

The latest spotfire has erupted in residential disability care, where just over six per cent of people have been vaccinated.

Mr Hunt insists the government was always intending on inoculating aged care residents first despite disability being in the same phase of rollout.

"We were always going to do this in stages based on the highest risk," the health minister told ABC radio on Wednesday.

Of the 910 coronavirus deaths in Australia, 685 have been in aged care.

"That's been the highest of the priorities. Now we move on the in-reach next week in the disability (sector) and that follows the order and priority that was always intended," Mr Hunt said.

But senior health officials have conceded the disability rollout is behind pace.

Health department associate secretary Caroline Edwards said 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.

The government also intends to visit people with disability who are unable to leave home from next week.

Health department boss Brendan Murphy said he hoped to have all vulnerable Australians 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," he said.

A union survey of 254 people found 85 per cent of aged care workers were unvaccinated, sparking fears one of the most likely routes of transmission remains open.

Mr Hunt said 36,000 aged care workers had received a jab.

"We have to start somewhere and finish somewhere," he said.

The minister said claims there were millions of missing doses were false with 600,000 made available this week and the same number set to be distributed next week.

He said having enough doses available for second shots made up the balance, while 1.7 million jabs had been administered.

Medical advice recommending the AstraZeneca vaccine only be used for people over 50 and global supply issues have rocked the rollout.

Pfizer will be primarily used for under-50s.

Labor argues the government should have diversified its vaccine portfolio to avoid the problems plaguing the program.

Mr Hunt said vulnerable people remained the priority but there was strong support from doctors to bring forward the rollout to people over 50.

"It's clear there is sufficient supply of AstraZeneca to do this," he said.