Medical experts warn a push by payday lenders into loans for elective and cosmetic surgery could lead to a rise in risky procedures and put people's health at risk.
Lenders are looking for new revenue streams following a crackdown into the sector by the corporate regulator.
MoneyMe, which was set up two years ago and offers small credit and cash advance loans, said it was expanding into large personal loans and "health finance" loans, both aimed at young people.
The loans come with an interest rate of up to 35 and 25 per cent respectively and the latter would be offered to patients as they leave a doctor's or dentist's office.
MoneyMe chief executive Clayton Howes said young people were the company's target demographic.
"The millennial consumer is becoming more and more fond of spending their money on lifestyle choices, and that extends further than $5000 for a holiday," he said.
"Instead of going overseas, they can get their surgery done locally."
He said young people liked the "freedom and flexibility" of getting money instantly.
"They are able to apply for $10,000 and have it delivered to their bank account, really really quickly," he said.
Professor Merrilyn Walton of the University of Sydney Medical School, said loans for elective and cosmetic surgery would potentially breach new guidelines for the industry, which require a "cooling off" period for major surgery.
She said it would fuel what was already an unsafe industry and lead to people making fast and risky decisions about their health.
"The cosmetic surgery industry is unregulated, which for me means it's ripe for financial exploitation," she said.
"Cosmetic surgery is not like buying a car, it's a medical procedure."
Online lenders are seeking to capitalise on new technology they say allows them to assess people's creditworthiness with a simple algorithm.
It follows a major crackdown of responsible lending practices by the corporate regulator, which lead to a government review considering tougher rules for the sector.
Consumer rights group the Consumer Action Law Centre said it was highly concerning loans would be pushed on people coming out of a doctor's or dentist's office.
"These industries really do know that when you are trying to sell something through an add-on sales process, people aren't in the right frame of mind to assess the deal they're getting," a spokesperson said.
"Their focus is on the medical procedure, not getting the most appropriate financial product."
Online lenders are in the spotlight over their use of technology or algorithms to assess people's creditworthiness.
This follows action by the corporate regulator against payday lender Nimble, which was forced to refund $1.6 million to more than 7000 customers in March after it was found to engage in irresponsible lending.
Mr Howes said MoneyMe could approve customer loans within 48 hours through technology that used algorithms to scan applicants' bank account statements and make "behavioural" assessments.
He said it was not encouraging people to get cosmetic surgery. "We are not a promoter of any service," he said.
Alan Jones, a spokesman for the Australasian College of Cosmetic Surgery, said the college did not condone doctors offering finance facilities to patients.
"Some people may be particularly vulnerable and make impulsive decisions," he said.
