Rio Tinto has three rare red diamonds from its Argyle Diamond Mine in its annual tender for the first time in 30 years.
The largest is a 1.56 carat round gem named Argyle Phoenix.
Overall, AAP reports 64 diamonds were on show from Argyle. Also in the collection are 58 pink and three blue diamonds.
Argyle pink diamonds manager Josephine Johnson said different markets around the world have preferences for different coloured diamonds.
She said the Japanese preferred pink diamonds while Europeans and the US market have a fondness for the rare red diamonds, which they buy as collector's items.
"Purplish pink ones are sought after in Japan because they reflect their cherry blossom colour," she said.
"They have a romantic view of the diamond. There's a strong engagement market in Japan."
Australia is Argyle Diamonds third largest market behind Japan and the United States.
AAP reports tender viewing of this year's collection will be held in Perth and Hong Kong, with previews in Sydney, New York and Tokyo. Bidding opens in August and closes in October.