"Mahela has done a decent job since taking over from Marvan Atapattu and he will continue till the World Cup," De Mel said.
"We've been working towards the World Cup and we want to make sure that Mahela feels comfortable ahead of the tournament which is not too far away."
De Mel said the decision to reappoint Jayawardene was made before he was named the Captain of the Year at the International Cricket Council's awards ceremony in Mumbai last week.
Jayawardene, 29, beat other high-profile nominees like Ricky Ponting of Australia and Rahul Dravid of India for the prestigious award.
The selectors persisted with Jayawardene despite Sri Lanka's failure to make the semi-finals of the Champions Trophy in India, although the team had been one of the favourites.
World champions Australia won the tournament in Mumbai on Sunday, defeating the West Indies by eight wickets in the final.
The Sri Lankan media reported that Jayawardene's authoritarian leadership during the Champions Trophy was n