Defence ministers from the 28-nation military alliance will discuss the full force, which can react quickly to any hotspots in Europe, when they meet on 5 February.
Stoltenberg said countries responsible for providing the several thousand troops should be known next week. Norway, Germany and the Netherlands are ready to contribute.
The forward units will comprise a few dozen troops only. They will plan and organize military exercises, and provide command and control for any reinforcements the force might require.