Federal Health Minister Sussan Ley has agreed to partly pay back the cost of four trips to the Gold Coast where she and her partner own two properties.

Key points: Sussan Ley has travelled to the Gold Coast 20 times over three years, the ABC finds

Sussan Ley has travelled to the Gold Coast 20 times over three years, the ABC finds The purchase of the apartment "was not planned nor anticipated", a spokesperson said earlier

The purchase of the apartment "was not planned nor anticipated", a spokesperson said earlier Ms Ley asked the Department of Finance to review all her ministerial travel to the Gold Coast

There are unanswered questions about 14 other taxpayer-funded trips identified by the ABC, including two New Year's Eve celebrations on the tourist strip.

During one trip in 2015, Ms Ley purchased an almost-$800,000 apartment, prompting the Opposition to call for her resignation.

She purchased the property while travelling to Queensland on ministerial business, accompanied by her partner.

The full cost of their trip was $3,125 — paid for by taxpayers.

In a statement, Ms Ley apologised for the "error of judgement" and said it did "not meet the high standards" set by the Prime Minister.

"While attending an auction was not the reason for my visit to Queensland or the Gold Coast, I completely understand this changed the context of the travel undertaken," she said.

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

Ms Ley will also pay back two other accommodation claims on the Gold Coast and a flight.

She said she had asked the Department of Finance to review all of her ministerial travel to the Gold Coast.

Other trips in question

The ABC has analysed three years' worth of the minister's travel reports and found she travelled to the Gold Coast 20 times.

As the sun set on the final days of 2013, Ms Ley charged taxpayers $655 for her flight to the tourist strip for New Year's Eve.

A year later, after another Gold Coast New Year's Eve, she charged for her and her partner's flights back to Sydney.

The most expensive flight was a $12,365 charter flight taken in March 2015.

The ABC put questions to Ms Ley's office about 18 trips, worth $53,877.

She declined an interview, but her office issued a statement saying: "In her portfolio, she is required to undertake extensive meetings with doctors, patients and other organisations that are not media or public events."

Sussan Ley is under fire for buying a $795,000 unit in this building on the Gold Coast. ( AAP: Scott Bailey )

Apartment purchased from LNP donor

A spokesperson for Ms Ley earlier said the purchase of the Surfers Paradise apartment "was not planned nor anticipated".

The apartment's previous owner Martin Corkery confirmed the sale, but said he did not know that Ms Ley was among the potential buyers.

Mr Corkery — who donated $50,000 to the Queensland LNP in 2011 — told ABC News he was overseas during the auction and only discovered the minister had bought the unit once he received the contract.

In an earlier statement, a spokesperson for Ms Ley said she had travelled to Brisbane to announce health funding before meeting with "local health stakeholders" 80 kilometres away on the Gold Coast.

"Minister Ley's partner was invited to accompany her to a function in Sydney on the Friday evening," the statement read.

"He then travelled with the Minister to Queensland under family travel arrangements.

"The EMB [Entitlements Management Branch] was consulted at the time to confirm Ms Ley's partner's travel was within the rules."

The spokesperson also stated all travel undertaken "was in accordance with the rules".

But Labor MP Catherine King earlier said while it remained unclear if Ms Ley broke any parliamentary rules, the purchase and its claimed nature did not pass the pub test.

"I think she's got some explaining to do, to explain how purchasing a luxury apartment with her [partner] is in any way, shape or form official business," she said.

"In anyone's world, $700,000-plus is a lot of money.

"I don't know too many people who would spend that sort of money, even if they had it, on an impulse. It's a pretty unbelievable claim."

How much did your local MP spend?

Explore how much your local politician spent from January 1 to July 30 in 2015 with our interactive chart, ordered from the politician with the most expenses claimed to the least.

Some past politicians will also appear, having lodged prior expenses with the Department of Finance during the six-month period.