The royal commission into Australia’s aged care sector comes amid a “rising torrent” of concern over safety and quality but is a “once-in-a-lifetime” opportunity to forge a better path, the inquiry has been told.

Opening a near year-long investigation of the industry in Adelaide on Friday, one of two commissioners Lynelle Briggs said the nation’s aged care system should be world class – one simple to understand, easily navigated and accessible to all.

“But, there has been a rising torrent of concern that the aged care system is faltering in certain areas of safety and quality and that it may not be fit for purpose,” she said.

“We need to ensure that all Australians have confidence the system will deliver for them and for their families.”

Fellow commissioner Richard Tracey said the inquiry was a once-in-a-lifetime opportunity to come together as a nation and create a better system of care for elderly Australians.

“The hallmark of a civilised society is how it treats its most vulnerable people and our elderly are often amongst our most physically, emotionally and financially vulnerable,” he said.

“Frail and elderly members of our community deserve to, and should, be looked after in the best possible way and we intend to do our best to see that happens.”

The royal commission, which will be based in Adelaide but hold hearings in other states, will examine the extent of sub-standard care and consider how services can be improved.

It was sparked in part by the revelations of abuse and poor treatment of dementia patients at Adelaide’s state government-run Oakden nursing home.

Whistleblower Stewart Johnston expressed anger on Friday that he and other Oakden family members were forced to watch proceedings from a separate room to make way for lawyers and industry representatives.

Mr Johnston said he was “dumbstruck” to be insulted in such a way and concerned to hear that advocacy groups and commission staff had already engaged in roundtable meetings to find out what had gone wrong.

“They’re asking the people that created the problem, how to fix it,” he said.

In his opening address counsel assisting the inquiry, Peter Gray QC said it was older Australians and the generations before them who had shaped the nation.

“They deserve the best care we can give them,” he said.

“There is evidence that they are currently not getting it.”

Mr Gray also revealed that the commission had already taken more than 300 public submissions with 80 per cent related to the provision of care in residential facilities.

Most raised issues concerning safety, medication management and nutrition.

The aged-care industry said it did not fear the scrutiny of the royal commission.

“We have zero tolerance for abuse and neglect where it occurs, and we are committed to continuous improvement to address problems as they arise,” Aged and Community Services Australia chief executive Pat Sparrow said.