Scott Morrison has brushed off calls to refer another marginal seat MP to the High Court to determine whether he is in breach of the Constitution.

Labor has accused the Morrison government of running a “protection racket” for Liberal MPs amid questions over the eligibility of Peter Dutton and Chris Crewther. 

But the opposition stopped short of endorsing the referral of Labor’s new recruit Dr Brian Owler or independent Dr Kerryn Phelps, who both face allegations that Medicare payments could represent an office of profit under the crown.

“These stories they come and they go and I frankly think the Australian people are completely over it,” Mr Morrison said.

“I have no concerns on the matter.”

The fresh allegations around Mr Crewther relate to a report in the Herald Sun that he bought a stake in a Mornington-based pharmaceutical company Gretals Australia that he had previously spruiked in Parliament. 

In a speech to Parliament, he specifically noted that the company secured government grants.

Labor alleges this could fit the criteria for a direct or indirect office of profit under the Crown.

“I have fully complied with my disclosure obligations and I am confident they do not raise any concerns,” Mr Crewther told The New Daily.

But shadow-attorney general Mark Dreyfus went on the attack in Melbourne. “It is beyond belief,” he said.

“We are talking about a very serious constitutional issue here, which regrettably the Prime Minister has completely dismissed with a wave of his hand.

“Has he already sought advice from the solicitor general? It is arrogance in the extreme from a desperate Prime Minister,” Mr Dreyfus said.

“He is running a protection racket for Mr Dutton and Mr Crewther.” 

The Coalition is bracing for the return of Parliament after the government lost the seat of Wentworth and a majority on the floor following the resignation of former Prime minister Malcolm Turbull. 

Mr Crewther has been the federal member for Dunkley since 2016. The seat covers the south eastern outskirts of Melbourne including the suburbs of Baxter, Frankston, Frankston North, Frankston South, Langwarrin, Langwarrin South, Mt Eliza, Mornington, Seaford and parts of Skye.

Before entering parliament the qualified lawyer worked in the ACT’s Supreme Court and internationally at Kosovo Property Agency through the United Nations, 2010-12.