Former Coalition ministers who oversaw the “vicious” Robodebt scheme face the growing threat of potential legal action over their roles in the illegal program.

On Tuesday, a leading law firm said it had already taken instructions from some Robodebt victims about possible claims, following last week’s scathing royal commission report.

It came as a senior Liberal described the unlawful scheme as “incredibly regrettable”.

“We’ve welcomed the report and apologised to the victims of Robodebt and we’ve taken it very seriously,” Coalition frontbencher Senator James Paterson said on Tuesday.

Government Services Minister Bill Shorten said Robodebt was a “shameful scandal in Australian political history”, and warned that many Australians wanted accountability following the royal commission’s findings on the multibillion-dollar program.

“I have watched the [former] Coalition ministers say that merely because they have been referred to a criminal body, or to some other regulatory authority, that somehow it has given them a clean bill of health,” he said on Tuesday.

“I suspect that there will be some individuals who seek legal advice and they may well seek a remedy of suing the individual former ministers – and that is why said last night I don’t know why these ministers are running around acting like they are out of the woods yet.”

“Ministers may seek indemnity and say that they were carrying this out as part of their ministerial role. This will be for lawyers to work through. I would just say that there is a lot of people out there who want accountability until they see accountability.”

The royal commission found the former ministers, including ex-prime minister Scott Morrison, dismissed or ignored concerns about the scheme’s legality.

Mr Morrison has rejected its findings that he misled cabinet. Other former ministers, including Stuart Robert, Alan Tudge and Christian Porter, were also named in commissioner Catherine Holmes’ report.

Mr Shorten told the ABC’s 7.30 on Monday that he was “perplexed” by some of the responses.

“This royal commission has a long way to go and a lot of lessons to be applied,” he said.

“It (Robodebt) was a poor-shaming, welfare-attacking, vicious attack, and … it was unlawful from the get-go.”

On Tuesday, Mr Shorten urged the opposition to work with the federal government on the fallout from the royal commission.

“I think having former prime minister Morrison say he did nothing wrong makes it very hard for the opposition to be taken credibly if they want to work with us,” he said.

“We have to stop treating people who may have fallen on hard times as second-class Australians. That is the first sea change in the Coalition’s rhetoric about the poor and vulnerable, the people who use welfare, [that] needs to change.

“Beyond that, we need to make sure that whenever there is a decision made by government that people … can see the logic, they can see the transparency – and we don’t ever again reverse the onus on how the government comes down on individuals and say you are guilty until proven innocent.”

• Bureaucrat’s days numbered, as Robodebt uncovers bigger issues

Senator Paterson said the Coalition would consider measures brought forward by the government in a bipartisan way.

“What action individuals choose to take as a result of this inquiry is a matter for them, and I’m sure will follow the usual legal processes involving government proceedings,” he said.

Meanwhile, class action lawyer Peter Gordon said his firm had written to Prime Minister Anthony Albanese following the report’s release, requesting compensation.

Gordon Legal led the the class action lawsuit in 2020 that the former government eventually settled for more than $1 billion, after a court ruled the automated debt recovery scheme was unlawful.

Gordon Legal senior lawyer Andrew Grech said if the firm was given a chance to use evidence from the royal commission in a civil claim, he expected there would be “serious repercussions for the individuals involved”.

“We always suspected that something along these lines is what had occurred, but there is a huge difference between knowing a thing and being able to prove a thing,” Mr Grech told the ABC.

“What I think the royal commission demonstrates is those proofs are available.

“I would summarise as ‘watch this space’.”

Mr Gordon said the firm already had instructions from some Robodebt victims and was “exploring a number of legal avenues”. They include a claim of misfeasance in public office – both a civil tort and a crime – “and a range of other causes of action”.

“The settlement approved was for the claim in unjust enrichment. It did no more than get the money back the government had stolen, and then provided for $110 million in interest and other minor forms of damage,” he told The Guardian.

“We have always said there was no opportunity on the pleaded causes of action to recover damages for pain and suffering, for other forms of loss, for example, if they lost their homes or job opportunities. There was nothing for distress and no punitive damages.”

Ms Holmes wrote in her report there was no practical way of setting up a compensation scheme for Robodebt victims.

Instead, while not a formal recommendation, she said a “better use of the money” would be to “lift the rate at which social security benefits are paid, to help recipients achieve some semblance of the ‘security’ element of that term”.

-with AAP