Disability service workers urgently need more support from state and federal governments as COVID-19 has caused severe staffing shortages, according to union officials and the industry's peak body.

National Disability Services chief Laurie Leigh on Friday told AAP some providers had lost up to 30 per cent of their workforce because staff were either isolating or sick with the virus.

Most providers, she said, had lost five to 15 per cent of staff.

The NDS chief said lack of access to rapid antigen tests and workforce shortages were the two largest headaches for the sector.

"The current wave of COVID-19 infections is putting significant strain on the provision of disability services," Ms Leigh said.

Health and Community Services Union official Roisin McGee said staff shortages had heaped more pressure on workers already suffering from burnout.

She called for the sector to have priority access to free rapid antigen tests. Workers could then prove they are able to provide COVID-safe care to clients without spending hours waiting in line for a PCR test and days for the result.

"This industry has already been cut to the bone, but staffing numbers are now at the minimum safety level," Ms McGee told AAP.

"It's dangerous for workers and worrying for people with a disability who need support.

"The staff who are still working now - they've worked through pandemics, lockdowns, seeing their colleagues get sick and maybe die. And now they've seen their fellow employees burn out and leave."

She also said that in Victoria, delays surrounding the NDIS screening check - which ensures workers do not present an unacceptable risk to participants - had ballooned out to up to 12 weeks.

One service provider had 130 potential new workers waiting for their application to be processed, Ms McGee said.

"The NDIS check is important, but it can't come at the expense of disabled people's care," the union official said.

On its website, the Victorian Government has warned the national police checking service is experiencing "unprecedented use of the system".

It says offline applications have been temporarily delayed up to eight weeks.

Meanwhile, the Australian Services Union has called on both the Commonwealth and NSW governments to provide disability service workers with paid isolation leave.

A survey of 700 ASU members found more than one in 10 working in the NDIS had contracted COVID since November.

Of those who caught the virus, 23 per cent did not have access to paid leave from their employer and did not have access to any government payments.

"Our members are under extreme pressure," ASU NSW/ACT branch acting secretary Angus McFarland said.

"They are getting infected with the virus or becoming close contacts and having to take time off work without pay."

People With Disability Australia president Samantha Connor said the disability service staffing shortages had the put the lives and health of thousands of vulnerable people at risk.

"We've had reports of people not getting basic assistance for days on end, people sleeping in their wheelchairs because there's no one to help them get into bed," Ms Connor said.