Online publisher Mamamia has released a statement late on Friday afternoon defending the recent charity auction of an unpaid internship for $10,000.

The "intensive" two-week internship was auctioned at a lunch in Sydney on Thursday to raise money for the charity Caritas Australia.

But the sale of the internship - described on the listing as "priceless" - prompted backlash on social media, with many accusing the company of exploiting unpaid workers.

lol Mamamia is auctioning things at the Caritas Women For The World lunch, including this "priceless" internship pic.twitter.com/bZC5wDoIha — Michael Roddan (@MichaelRoddan) May 5, 2016

"Mamamia was not involved in the promotion of the auction item and was not responsible for the description of the internship as 'priceless'," the statement read.

"This was done by organisers presumably – and understandably- to maximise the amount raised for the charity."

Mamamia's publisher Mia Freedman said: "only on Twitter could $10K raised for charity be something to be angry about".

Ms Freedman also re-posted a tweet from a user named 'HayleyC', who seemed to imply she was the winning bidder.

"Am very much looking forward to my internship at @Mamamia. Money is not a concern, looking forward to the experience," she wrote. Her Twitter bio identifies her as a first-year arts student.

But other Twitter users said the charity aspect of the auction did not justify the sale.

Australia's leading media union, the MEAA, tweeted a link to a report on the auction with the hashtag "#paythewriters", despite Mamamia's statement saying its internship program "fully complies with MEAA guidelines".

Others accused Mamamia of elitism.

C'mon, someone profile mamamia's $10k internship winner and tell me about merit and hard work and a fair go for all — Asher Wolf (@Asher_Wolf) May 5, 2016

There are issues with internships generally but the auctioned Mamamia internship has the added sting in the tail of privilege over merit. — Michael Byrnes (@MichaelByrnes) May 6, 2016

@AskBossy @BenFordham @Mamamia you'd do better and it would be in the spirit of the event to donate internships to underprivileged women — Rachael Lonergan (@RachaelHasIdeas) May 5, 2016

The Mamamia internship controversy comes a amid wider debate over the value of internships, triggered by the announcement of a new federal young employment scheme announced in the Budget.

The Youth Jobs Path program will see 30,000 internships offered to young people who have been out of work for six months or more. Treasurer Scott Morrison described the program as "real work for the dole", with internship recipients to be given a bonus of $200 a fortnight on top of their regular welfare payments.

But the program has drawn criticism from Interns Australia, which cautioned the internships could result in companies replacing workers on proper wages with underpaid interns.