Labor says former foreign minister Julie Bishop's appointment to the board of an Australian-based overseas aid consultancy firm doesn't pass the pub test.
Julie Bishop is the latest former minister whose post-politics career choices have sparked calls for the prime minister to uphold ministerial standards.
The Opposition says the former foreign minister's appointment to the board of private overseas aid consultancy firm Palladium appears to be a breach of the standards.
Ms Bishop said looked forward to continuing her long-standing interest in economic development in the Pacific and beyond in the role.
The standards say retired ministers must not "lobby, advocate or have business meetings with members of the government, parliament, public service or defence force" for 18 months after leaving parliament on matters they dealt with in their final 18 months in politics.
The opposition says Ms Bishop had been appointed because of her global network of contacts.
"Not only doesn't it pass the pub test, it looks on the face of it like another breach of the ministerial standards," Labor foreign affairs spokeswoman Penny Wong told ABC News on Tuesday.
Senator Wong says Palladium profited from decisions Ms Bishop made when she was foreign minister.
"In excess of $500 million from what we can ascertain."
The announcement of Ms Bishop's appointment follows former defence minister Christopher Pyne decision to take up a defence-focused gig with professional services giant EY.
Mr Pyne and Ms Bishop say they will comply with the ministerial standards but Senator Wong said it was up to the prime minister to act.
However, Labor isn't committing to supporting a Centre Alliance move to establish a Senate inquiry into compliance with ministerial standards to examine the postings.
Greens want inquiry to examine Frydenberg, Taylor
The Greens are seeking to have Centre Alliance Senator Rex Patrick's inquiry broadened to look at whether Energy Minister Angus Taylor and Treasurer Josh Frydenberg breached the ministerial code over discussions about a critically endangered grassland species.
Greens democracy spokeswoman Larissa Waters has accused the current ministers of flouting rules designed to avoid conflict of interest.
The Guardian reported last month, Mr Taylor discussed the status of critically-endangered grassland species with Mr Frydenberg while a company he part owns was being investigated for illegal land clearing.
The Greens also want to give the code more teeth and extend the cooling off period for post-parliamentary employment.
"It's no wonder that the Australian people think that we all have our snouts in the trough," Greens democracy spokeswoman Larissa Waters told reporters.
"It shouldn't be up to the prime minister to either decide to enforce or not enforce his own rules.
"He's just patting them all on the tops of their heads and saying, 'Don't worry about it mate, she'll be right'."
Ultimately, she wants to see an independent parliamentary integrity commissioner to rule on these kinds of cases.
Mr Pyne's new employer, EY, referred to a statement it made last week confirming he would provide occasional high-level strategic advice that did not involve him providing or using any information he may have received as a minister.
The former MP of 26 years insists no one has been able to point to any instance of a breach of the code.
Additional reporting by AAP