NATO chief Anders Fogh Rasmussen will Saturday call on cash-strapped US and European alliance members not to cut funds after it stops combat operations in Afghanistan in 2014, DPA reported.
"Not cash in what some perceive as the post-ISAF dividend," he says in the speech, referring to the International Security Assistance Force in the country.
"In this age of austerity, that looks like an attractive option. But it would be the wrong option. Because security challenges won't wait while we fix our finances."
The NATO secretary general warned that, while the US and EU struggle economically, "more cuts now will lead to greater insecurity in the future, at a cost we simply can't afford."
"We saw this after the Cold War, when we were ill prepared to respond to the crises in the Balkans."
Rasmussen was due to deliver his speech at the annual Munich Security Conference, a meeting that looks at trouble spots from Mali to Syria and the wider Middle East conflict.
He was due to outline in his speech a vision for "our alliance shifting from operational engagement to operational readiness. From campaign to contingency. From deployed NATO to prepared NATO."
Looking at the looming Afghanistan combat troop withdrawal, he said "the end of NATO's biggest operation presents us with a big opportunity."
"An opportunity to generate key capabilities. To engage robustly with new geopolitical realities. And to rebalance our priorities and commitments. In other words, an opportunity to plan for the future."