"We are proud of him and wish him success," Murthy said in his first comments since the Indian-origin Sunak was elevated to the top post after Penny Mordaunt dropped out of the race.
"Congratulations to Rishi. We are proud of him and we wish him success," Murthy said, adding, "We are confident he will do his best for the people of the United Kingdom," news agency PTI reported.
Sunak, the son of a pharmacist mother and doctor father, was educated in Winchester, and then Oxford. He then spent three years working at the Goldman Sachs Group Inc and completed his MBA from Stanford University.
The 42-year-old became an MP in 2015 from Richmond, and has served as the Chancellor of the Exchequer and the Chief Secretary to the Treasury previously.
Sunak is scheduled to be appointed to the post of PM on Tuesday, 25 October, after meeting King Charles III.
(With inputs from PTI.)