The rollout of the National Disability Insurance Scheme (NDIS) to eligible adults will begin in South Australia from tomorrow, with Adelaide's north and the Barossa among the first regions to benefit.

The milestone follows a lengthy trial period, which lasted several years, as well as an embarrassing IT meltdown that led to payment delays, and other problems such as staff not receiving training.

Until now, only children had access to the scheme in South Australia.

The phasing-in period is expected to take 12 months, with the full rollout expected to be completed by July next year.

NDIS rollout dates in SA From July: northern Adelaide, Barossa, Light and Lower North

northern Adelaide, Barossa, Light and Lower North From October: north-eastern Adelaide, Murray Mallee, Limestone Coast,

north-eastern Adelaide, Murray Mallee, Limestone Coast, From January: southern Adelaide, Fleurieu, Kangaroo Island, Yorke Peninsula, Mid North, Far North, Eyre Peninsula and West

southern Adelaide, Fleurieu, Kangaroo Island, Yorke Peninsula, Mid North, Far North, Eyre Peninsula and West From April: western Adelaide, eastern Adelaide and Adelaide Hills

The State Government said more than 32,000 South Australians would receive services under the full scheme, compared to around 17,000 beforehand.

Premier Jay Weatherill said the NDIS would put people with disabilities "at the centre of decision-making about the support they receive".

"For the first time, people with disability will be able to choose the support they need to live the life they want to live," he said.

"That will mean different things for each individual."

The Adelaide's northern suburbs, the Barossa and the Light and lower north regions will be the first to receive the scheme.

It will be extended to areas including the north-eastern suburbs and Murray Mallee in October, and then to the city's south, Fleurieu, Yorke and Eyre peninsulas in January.

Patients in the Adelaide Hills and the city's west and east will be the last to join, with the rollout in those areas to begin in April.

The Government said it would invest $723 million each year into the NDIS.

It said the number of jobs in the disability sector is expected to double, from 6,000 to 12,000, once the scheme is fully introduced.