The firm now had a third of a 10 million kilo branded tea market.
Sri Lanka's total domestic tea consumption is estimated at around 26 million kilos.
He said the company started selling BOPF grade tea in to the domestic market when others we selling grades lower than that.
It buys tea from the auctions and not just from its group-controlled Watawala Plantations as its production is not sufficient to meet the volume of the particular grade and to maintain a consistent taste across the year.
Govindasamy said Watala Plantations became the largest producer of tea among Sri Lanka's largest regional plantations companies in 2012.
The firm had benefitted from a partnership with Tata Global Beverages, officials said.
The group has also been diversifying heavily into palm oil. Its marketing arm also has a branded palm oil, Oliate in the market.
Sunshine Holdings also has interests in pharmaceuticals and energy.
Sunshine Holdings, through its marketing unit, already sells 'Zesta