Ms Ley's decision followed a conversation with Prime Minister Malcolm Turnbull in which he said she had not met the standards he expects of ministers.

Ms Ley had come under intense pressure to provide a full explanation of the May 2015 trip or resign from the ministry since it was revealed on Friday.

Ms Ley originally said the apartment purchase, made after a health announcement in Brisbane, was "not planned nor anticipated" and that she had ministerial duties to fulfill on the Gold Coast. That claim was questioned after subsequent revelations that her partner owns a business located near the unit and that it was purchased from a Liberal donor.

In a statement released on Sunday afternoon Ms Ley said the apartment auction was not the reason for her trip to the Gold Coast but she understood the purchase had "changed the context of the travel undertaken".

"The distinction between public and private business should be as clear as possible when dealing with taxpayers' money," she said.

"I have spoken to the Prime Minister and he agrees that this claim does not meet the high standards he expects of ministers. I apologise for the error of judgment."

Ms Ley said she would ask the Department of Finance on Monday to invoice her for all the costs of car and travel allowance claimed for the trip and to apply any penalties for erroneous claims. 

Ms Ley and her partner charged taxpayers $3949 for flights during the two-day trip.

Ms Ley said an examination of her travel records had revealed two other claims for accommodation in the Gold Coast where she should have in fact stayed in Brisbane. She will repay the cost of these claims as well as a flight from Coolongatta to Canberra in June 2015. 

Ms Ley said her travel to the Gold Coast was "within the rules" but that she had decided to repay the travel claims because she holds herself to high standards.

She said she had travelled to Brisbane on 9 May 2015 to make an announcement about the availability of new medicines at a specialist breast cancer clinic before going to the Gold Coast to meet with patients.

She said she stayed in the Gold Coast that night because she was due in Canberra the following the day.