Labor has called on Prime Minister Tony Abbott to make a call in the case of a junior minister suspected of breaching parliamentary standards.
National Party senator and Assistant Health Minister Fiona Nash has faced repeated questioning over her office's involvement in the removal of a food-rating website.
Her chief of staff resigned after being linked to a public affairs company that represented junk food industry clients who opposed the healthy living online reference.
"Public health experts have publicly questioned whether Senator Nash is the most appropriate minister to represent the preventative health portfolio," opposition health spokeswoman Catherine King said.
Labor said if reports were true that Mr Abbott knew of a possible conflict of interest in Senator Nash's office, he should address the issue.
"It is not satisfactory for the prime minister to say nothing on this matter indefinitely," Ms King said.
