Labor has called on Health Minister Sussan Ley to explain why she bought an investment property on the Gold Coast during a taxpayer-funded trip classified as official business.

The opposition's health spokeswoman Catherine King said Ms Ley must "front up today and explain" or resign.

Ms Ley said she had not planned to buy a Gold Coast ocean view apartment during a trip to Brisbane in May 2015 for a government announcement about an expansion of drugs included in the ​Pharmaceutical Benefits Scheme.

In a statement, Ms Ley's office said the minister travelled to the Gold Coast for meetings with health stakeholders after the announcement, but her purchase of the $795,000 Main Beach property had been unexpected.