Former captain Ranatunga, who already heads Sri Lanka Cricket (SLC), will be assisted by his World Cup winning colleague Aravinda de Silva in the body's interim committee.
"I have issued letters of appointment to Aravinda de Silva, Guy de Alwis and Ashok Pathirage appointing them as members of interim committee," Lokuge said.
The SLC's interim committee has been expanded to 10 members and the new appointments are in line with Ranatunga's policy of involving more former players.
De Silva, now 42, played 93 Tests and 308 one-day internationals between 1984 and 2002 and was regarded as one of the game's finest batsmen.
He was the man of the match when Sri Lanka defeated Australia in the World cup final in Lahore, Pakistan in 1996.
De Alwis was a former wicketkeeper-batsman who played 11 Tests and 31 one-day internationals between 1983 and 1988. Pathirage, a school-mate of Ranatunga, is a a successful businessman.