Authorities ordered the six-day shutdown from Thursday amid fears a cluster of coronavirus cases might spark widespread community transmission.

But that was quickly cut short on the basis of revised information provided by the man, who worked at an Adelaide pizza bar, who had previously indicated he only collected a takeaway meal from the venue.

Officials were highly critical of the man's actions and police have launched a major investigation into the circumstances.

On Tuesday, the man's lawyer issued a statement saying he did not foresee or intend what unfolded.

"He is extremely remorseful and deeply sorry for any part his conduct played in any unnecessary lockdown actions," the statement said.

"My client's current focus is on cooperating with the authorities and completing quarantine.

"He is sincerely concerned about the impact of the lockdown on South Australians."

The statement said the man had limited access to government information and public comments on social media, but believed some information was not fair or accurate.

In an update to the police investigation on Monday, Assistant Commissioner Peter Harvey said officers had looked through 400 hours of CCTV footage and had seized various electronic devices, including a phone and a computer.

He said investigators had identified two more people they wanted to speak with who were currently seeking legal advice.

Mr Harvey said his investigation would deal in facts, "not rumour and innuendo".

"We're really stepping back here. There's a lot of emotion and a lot of desire for something to happen," he said.

"But it will be done carefully, it will be done clinically and we'll put our case forward.

"There may not be a case, just the same there may well be, that's the point of the investigation."

Australian Associated Press