The price of Rooibos tea will rise by 15 percent from January next year because of supply constraints and growing demand, producer Rooibos Limited said on Tuesday.

"Not only has the worldwide demand for Rooibos increased, but the harvest in 2013 was not as big as initially projected," said company managing director Martin Bergh.

"Although production will increase during 2014, the demand will still outweigh supply and the reserve situation is becoming alarmingly low."

Bergh said society was clearly becoming more aware of the virtues of Rooibos tea.

Bigger exports did not mean less Rooibos for South Africans, he said.

"On the contrary, the biggest growth comes from Southern Africa."

The company did not have control over retailers and hoped that brand owners and retailers would absorb some of the costs.

"We are unsure of what effect the higher price will have on consumers and do not know what the increase in retail prices will be. We have no control over the value chain and cannot speak on behalf of the brands," Bergh said.