PureCircle, the food sweetener group, looks close to promoting the stevia plant to the list of plantation supercrops, after saying it is looking at tropical regions around the globe for expanding production.

The Malaysian-based group, announcing a  69% rise in underlying earnings, said that "highly encouraging" harvests of stevia in Kenya and Paraguay had spurred it to continue adding growers in these two countries

PureCircle added it was also investigating "plantation-scale growing opportunities" for the plant, a relation of the sunflower, in regions including South East Asia, South America and Africa.

"Progress continues in diversifying leaf sources," said PureCircle, which processes stevia leaves into a low calorie sweetener, named Reb A, which companies including Pepsi, Coca-Cola and Cargill are using as an alternative to sugar.

PureCircle estimates the market for plant-sourced alternatives to sugar at $10bn and growing, now that Reb A and some competitor products have received approval in Australia, New Zealand and the US.

Paul Selway-Swift, the PureCircle chairman said: "With widespread regulatory clearances and many major product launches, it is clear that this is going to be a large global industry.

"Our priority now is to ensure that we successfully scale up the business to meet the expected demand."

The group is expanding capacity at refineries in China and Malaysia.

In the half year to December 31, PureCircle raised earnings by 69% rise to $2.1m in underlying earnings, on revenues up 49% at $21.6m.

In London, PureCircle shares stood 1p higher at 163.5p in late morning trade.