Centre Alliance senator Rex Patrick has backed a call for companies that hire former ministers to lobby within the 18-month cooling off period to be excluded from government tenders, as another of the big four accounting firms moves to distance itself from Ernst and Young's hiring of Christopher Pyne.
Deloitte has told a Senate inquiry into Mr Pyne and Julie Bishop's new consulting roles it has tightened up its recruitment processes to include a "compliance check" to ensure its new hires aren't breaching the statement of ministerial standards.
"We understand the importance of adherence to the standards by former ministers, as well as our role as a significant employer to understand the standards and to mitigate any real or potential conflicts of interest in our employment and client engagement practices," their letter to the committee said.
But Senator Patrick said there should be real consequences for ex-ministers and organisations who flout the rules.
While the Grattan Institute suggested former ministers who breach the code - and the companies that hire them - should have their access to Parliament House revoked, Senator Patrick said that would hardly be a deterrent.
"The same meeting that could take place in Parliament House could easily take place in a restaurant in Manuka," he said.
Senator Patrick said a legal obligation needed to be created when a parliamentarian accepted a job as a minister so they would be forced to comply with the code after they left office.
"If it is broken, I think you could raise an application for a breach of contract and at a very minimum ensure no profit is obtained from the breach," Senator Patrick said.
He also said companies found to have breached the standards should be excluded from government tenders "for probity reasons".
"It's reasonable to say that by the time 18 months has passed, any commercial value associated with that information has eroded," Senator Patrick said.
Outgoing Prime Minister and Cabinet secretary Dr Martin Parkinson told the inquiry former ministers should be able to get a job after they left parliament, even if their new role related to their portfolio.
"However, it is important that former ministers do not misuse the knowledge and information they have gained from their ministerial positions to benefit themselves or others," Dr Parkinson said.
But Senator Patrick said there was nothing wrong with Mr Pyne taking a role on the board of a hospital or as an advocate for a community organisation.
"If Christopher Pyne had walked out of his role as a defence minister and walked into a manufacturing company of some sort it would not create a conflict in the same way as walking out and working for a defence company does," Senator Patrick said.