Velebit became a member of the Yugoslav Communist Party in 1939 and joined the resistance movement in 1941. He was a National Liberation Army envoy to Egypt and Italy and was head of the military mission to London from 1943 to 1945.
After World War Two he served as assistant foreign minister and ambassador to Italy and Great Britain. He was also a member of the UN Economic Mission for Europe and a director in the Secretariat of the International Labour Organisation in Geneva.
He was also a member of the Council of the non-parliamentary Socialist Workers' Party (SRP) in Croatia.
Velebit will be cremated at Zagreb's Mirogoj Cemetery on Friday.