Kotromanovic said Montenegro's integration into NATO would represent new progress in the security consolidation of Southeast Europe and the Mediterranean.
"There's no doubt about that and I believe there's no doubt that it will happen," he was quoted as saying in Sunday's Pobjeda.
He said Croatia was not alone in believing that NATO's next summit should be an enlargement summit.
Asked what Croatia had gained by joining NATO, Kotromanovic said "a stable and long term security prospect which belonging to the strongest defence alliance in the contemporary world brings."
"In the political sense, we have the possibility of deciding, together with other NATO members, on the policies of facing the most important and the most complex security topics, even global ones. An important aspect of membership in the alliance is that, thanks to collective defence and joint planning, we don't have to increase defence funds to a level that our economy could not withstand," he was quoted as saying.