'Worst I've seen': Natalya Diehm reveals Paris bronze medal deteriorated within hours

Australia's Natalya Diehm said her bronze medal from the Paris Olympics started breaking apart within hours after taking third in the BMX freestyle.

Complaints have been made to the International Olympic Committee over the quality of medals won at the Paris Games, with more than 100 athletes saying their treasured items are falling apart.

The group of medal winners, including six Australians, expressed dismay since the end of the Games in August, with several taking their concerns to social media while alerting officials to the problem.

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Speaking to Fox FM in Melbourne, Diehm said she noticed the medal had changed when she got back to the athlete's village.

"For me, mine started happening day one. I received the medal, (had the) medal ceremony, did all the media stuff," she said.

"I got back to the Village at about 12 in the morning, and I looked down and I was like, 'Oh no, I've already scuffed it!'

"I licked my finger, gave it a bit of a rub, and the clear coat has rubbed off straight away."

The medals were designed by LVMH Moët Hennessy Louis Vuitton, which is a brand owned by France's richest family. Diehm said the coveted prize deteriorated more after the Games.

"It's honestly the worst bronze medals that I've seen, worldwide. Within two weeks, it was just looking terrible.

"When I first flagged it with the AOC (Australian Olympic Committee), they said they'll try work with the IOC to get this fixed.

"But they said it's not the first time it's happened; it happened in 2016 Rio Olympics as well. Hopefully we can get it fixed. The bronze seems to be the worst colour."

An investigation by the New York Times this week underlined issues relating to the medals, sparking an apology from Olympic bosses.

"Damaged medals will be systematically replaced by the Monnaie de Paris [the French mint] and engraved in an identical way to the originals," the IOC said in a statement.

Reports state none of the problematic medals are gold, with silver and bronze medals proving to be an issue.

According to The New York Times, Monnaie de Paris, which produced the medals, blamed the glitch "on a technical issue related to varnish".

"The mint discovered that the varnish used to prevent oxidation was defective," the publication reported.

"Its varnish recipe is a trade secret, but the coating was weakened after the mint changed it to conform to recent European Union regulations banning the use of chromium trioxide, a toxic chemical used to prevent metal from rusting, according to La Lettre, a French industry newspaper."