The presidential office Cheong Wa Dae on Tuesday denied rumors that it had purchased large amounts of medicines from a local pharmaceutical firm with the help of a doctor linked to President Park Geun-hye's confidante at the center of an ongoing corruption scandal.

Citing data from the state-run health insurance review agency, Rep. Kim Sang-hee of the main opposition Democratic Party claimed that Cheong Wa Dae purchased 20 million won (US$16,999) worth of medicines from Green Cross Corp. in March 2014 and August this year.

The list of medicines includes various injections for nutrition and skin care, triggering speculation that they were purchased for the president.

The presidential office said that the medicines were purchased legitimately to provide health services to all of its employees, including security officials, based on the judgment of the presidential medical staff.

At the time of the purchases, Kim Sang-man, a doctor known to have ties to Park's confidante Choi Soon-sil, worked for a hospital run by Green Cross Corp.

Choi is suspected of illicitly obtaining prescriptions for the president with Kim's help at Chaum, an upscale anti-aging clinic in southern Seoul. Kim had worked at Chaum until February 2014 before joining Green Cross.

After the health ministry filed a complaint late last week, the prosecution launched a probe into the allegations of illicit prescriptions, investigators said Tuesday.

It is illegal to issue a medical prescription without diagnosing a patient -- except for some special cases such as at the request of an immediate family member. (Yonhap)