Pacific Fresh chairman Frank Mercuri, who introduced the fruit into Australia, has said demand for the juicy fruit couldn't be sweeter.

Pacific Fresh has packed more than 30,000 boxes, up from last season's 8500.

Sumo mandarins are distinctive compared to other varieties - bright orange in colour, oval shaped with a top knot - giving them their name.

"It's been a really good season going all through August," Mr Mercuri said.

The demand for the Sumo is a force to be reckoned with, something Mr Mercuri attributes to the fruit's practicality.

"It's a bit of a big mandarin the Sumo, it's easy to peel, it's seedless, every 20 to 30 fruits you might find one seed, but that's all and it's real sweet," he said. "Mums like to put it in the lunchbox."

Mr Mercuri brought the plant to Australia in 2001, planning to export Sumos to Japan where the fruit can fetch a small fortune.

"They're very popular and cost $5 to $10 each," he said.

But protocols and regulations have thus far prevented Pacific Fresh from tapping into the lucrative Japanese market, something Mr Mercuri says will change in the future.

"It will happen in a few more years, but (at the moment) we're flat out keeping up (with Australian orders)," he said.

Sumo demand is expected to continue to raise, as Orange sales plateau.

"Navels are not going to increase," Mr Mercuri said.

Pacific Fresh currently distributes to Woolworth and Coles, who Mr Mercuri said have been incredibly supportive.

While the majority of growers remain in Leeton, Sumo mandarins have been grown in Sunraysia, Mildura for the first time.

However, Mr Mercuri is keeping his cards close to his chest, insisting it is important not to over plant.

"We don't want to over plant, they take a lot of tender loving care."