Now 20, Paul was born eight weeks premature with cerebral palsy. He needs help to be toileted, showered and fed and often needs to be lifted by his mum.

Speaking during National Carers Week last week, Ms Sheppard said caring for Paul was getting harder and becoming a strain on her health.

She unsuccessfully applied for part-time respite care at the Young Adults transition clinic at Monash Medical Centre.

Southern Health, which operates MMC, offers two community-based respite services. A spokeswoman said the waiting list for services was about two to three months, depending on which respite option was requested.

"The problem is, there's really not enough support out there," Ms Sheppard said.

"It's not just for me, it's something that would help make Paul more independent.

"We treat him as normal but I want him to be able to do what other kids do."

A spokesman for the Health and Community Services Union said funding for respite care was clearly lacking.

"We need to be encouraging people into the disability field, not scaring them away by being underpaid and undervalued."

Shadow Minister for Community Services Mary Wooldridge said the current system was in crisis and the demand for services far surpassed availability.

Victorian Government spokesman Michael Sinclair said funding for disability services had been steadily increased, including a landmark $478 million funding agreement between the State and Federal governments this year.