Funding for the facility has been called into question as original plans for a residential drug and alcohol rehabilitation centre for Indigenous people remain undelivered.

Designed as an eight-bed facility, the $12 million construction in Canberra's Tidbinbilla Valley has offered day-program support to 57 clients since late 2017.

Opposition Indigenous affairs spokesman James Milligan said the government had provided the funding with the understanding it would be a residential facility.

He called for an investigation into how the money was spent because an overnight facility has not been delivered.

Mr Milligan said the Financial Management Act 1996 prohibits the ACT government from using public money for anything other than in accordance with an appropriation.

The government abandoned the Indigenous community's proposal for a residential drug and alcohol centre after it was revealed the area was not zoned for clinical services.

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At an annual operational cost of $1.8 million, Ngunnawal offers clients mindfulness, music, yarning circles, land management and a healing program.

Mr Milligan said the government has the opportunity to correct its zoning mismanagement.

"For more than a decade, the community has been paying millions of dollars for a project that has never been delivered," Mr Milligan said.

"What we got has delivered little to know benefit to the community."

While there is no current procurement tender for a residential program at Ngunnawal, an ACT government spokesperson said the ACT Health Directorate had engaged the Healing Foundation - an organisation supporting stolen generations survivors, families and communities - to review and develop the model of care.

The spokesperson said a review into the development of a separate residential service supporting drug and alcohol rehabilitation for Aboriginal and Torres Strait Islanders in the ACT was also underway.

"ACT Health Directorate has engaged Winnunga Nimmityjah Aboriginal Health and Community Services to develop a culturally appropriate model of care for the proposed facility," the spokesperson said.

"The model of care will be finalised by July 31 2020, with design and construction to follow."