It comes as Bruce Lander highlighted the roles of Mental Health Minister Leesa Vlahos, Chief Psychiatrist Aaron Groves and Community Visitor Maurice Corcoran, who has repeatedly raised concerns about Oakden, as of likely key interest to his inquiry, and warned a standoff over access to cabinet documents – if relevant – could yet see him pursue the Government through the courts.

In parliament yesterday, Deputy Premier John Rau and the under-fire Vlahos referred repeatedly to the ICAC inquiry launched into potential maladministration over the disgraced Oakden Older Persons Mental Health Service as an “Ombudsman’s inquiry”.

Vlahos directly asserted that “the Ombudsman is having an inquiry in this space”, while Rau emphasised that Commissioner Bruce Lander was “conducting an investigation in a substituted capacity as the Ombudsman… using the provisions of the Ombudsman Act in that regard and therefore is not operating as the Independent Commissioner Against Corruption in this particular matter”.

The characterisation was first employed by Jay Weatherill in relation to the ICAC’s earlier investigation into the Gillman scandal.

But Lander told InDaily today he takes “strong issue” with the terminology.

“I’m very disappointed that the Government have characterised this as an Ombudsman’s investigation – it’s nothing of the kind,” he said.

“The investigation is being carried out by me as the Independent Commissioner Against Corruption, using the powers given to the Ombudsman under the Ombudsman’s Act – which effectively means the powers under the Royal Commissions Act.”

Both the Premier and the Deputy Premier well know that the investigation is being carried out by me as the Independent Commissioner Against Corruption

He insisted that “the Ombudsman investigates administrative acts”.

“I’m not investigating administrative acts – I’m investigating conduct, for the purpose of determining responsibility [and] I’m especially disappointed that the Government would characterise my investigation in that way.”

Asked if he believed the characterisation was politically-motivated, he replied: “I can’t think of any other reason.”

“Both the Premier and the Deputy Premier well know that the investigation is being carried out by me as the Independent Commissioner Against Corruption… I’ve had numerous conversations with the Deputy Premier about the powers under the act, and it’s especially disappointing he would characterise it in that way,” he said.

Asked if he considered the consistent downplaying of his role as tantamount to devaluing, blocking or undermining his investigation, Lander replied: “I think it could have that effect.”

“And whether that is the motivation or the purpose for the characterisation, I’m not sure, but because it could have that effect the Government should not characterise it that way publicly,” he said.

Weatherill turned down requests for interview today, with his office citing a busy schedule. However, he said in a statement that he “welcomed Mr Lander’s investigation into Oakden”.

“As the Commissioner has stated, he is the ICAC Commissioner exercising the powers of an Ombudsman. I agree with his assessment,” Weatherill said.

“The top priority for the Government is to improve conditions for residents at the Oakden facility and expedite their move.”

The latest standoff follows Weatherill’s insistence yesterday that cabinet documents would not be made available to the ICAC investigation, citing a “public interest protection”.

Lander told InDaily he was aware “of a protocol in relation to the production of cabinet documents that was developed after the Gillman inquiry”, in which cabinet documents were provided.

“That protocol was that the Government would look at each request on an individual basis,” he said.

“I haven’t yet made a request for any of those documents, so I’m a little surprised that the Premier has announced in advance that the documents won’t be provided.”

However, he continued, “there may not be any cabinet documents that are relevant because I understand that the Premier has said [the Oakden matter] never went to cabinet”.

Asked if this fact in itself could be relevant to his inquiry, he said “it could be, indeed”.

“Well, that’s a fact in the investigation which will be relevant to determining how the investigation will proceed,” he said.

“At some stage it may be necessary to write to the secretary of the cabinet office and request advice as to whether or not cabinet ever considered the Oakden facility, but it’s too early in the investigation to know whether that would occur.”

He said he may yet seek to obtain cabinet documents through the Supreme Court, but “I’d get advice on that at the time”.

However, he warned “if I conclude at the end of the investigation that the inability to have access to documents means I can’t make findings in relation to particular persons, I’ll say so.”

The Government has blocked his previous request to be able to conduct maladministration hearings in public, a decision he says could compromise the “integrity” of his investigation.

I’m really asking for that power to protect the integrity of the investigation

“I think there are good reasons to have public hearings in relation to maladministration, and very good reasons not to have public hearings into investigations of corruption,” he said.

“An investigation into maladministration gives rise to a decision by me… I have to decide whether public officers and public authorities have engaged in maladministration… and the public needs to know whether my investigation was carried out impartially and appropriately.

“And it can’t know that simply by me publishing my findings at the end of the investigation, so I’m really asking for that power to protect the integrity of the investigation.”

Lander said his inquiry would “have to consider responses [to Oakden] at a number of levels”.

“At the level of the minister, who has responsibilities under the mental health act, of the chief psychiatrist, who has responsibilities under the mental health act, and community visitors, who also have responsibilities under the act,” he said.

“The act codifies those responsibilities, so I have to determine whether they have discharged those responsibilities.”

He emphasised that “there are other people who might have had responsibilities at a lower level to those people” and he does not know what his primary focus would be “because I don’t know enough about it yet”.

“I could say this: they have to be considered in the investigation, those three people,” he said.

Weatherill last week told Channel 9 the ICAC inquiry was “not an investigation into [Vlahos], it’s an investigation into the Oakden matter”.

Lander “hopes” the inquiry will be concluded within six months, putting it within months of the looming March state election. However, he insists the timing “can’t be avoided”.

“The timeframe has been informed by the chief psychiatrist’s report… I couldn’t delay it till after the election – that would be inappropriate,” he said.

The Opposition will today give notice of an updated bill to allow public hearings for ICAC inquiries into maladministration matters, after Steven Marshall and his deputy Vickie Chapman met with Lander late this morning.

“I’ve given him advice that we’ll be progressing our push for public hearings here in SA,” Marshall told InDaily.

The Liberals voted in support of the Government’s bill last year, which updated the ICAC Act but did not allow for public hearings on matters of maladministration.

However the Liberals have long favoured a more transparent model, dating back to Isobel Redmond’s time as Opposition Leader.

Chapman has had a bill on the notice paper since 2015 allowing for public ICAC hearings in matters of maladministration.

“The simple fact is the people of SA want to know what happened, and the Government – true to form – is refusing to have open hearings,” Marshall said.

“This is just a continuation of the toxic culture of cover-up and secrecy.”