Nato Secretary General Anders Fogh Rasmussen arrived in Afghanistan on Monday to meet with President Hamid Karzai and Isaf commanders.
The Nato chief will also meet the other Afghan security officials and the Isaf commanders in Afghanistan to discuss the next steps in Isaf's campaign.
His visit comes after a meeting in Brussels February 21-22 where Nato members discussed a new proposal to sustain the number of Afghan troops at its peak of 352,000 soldiers through to 2018.
The new plan marks a shift from last year's meeting where Nato defence ministers agreed to reduce the number of Afghan security forces to 240,000 after 2014 in the wake of diminishing financial resources.
The current 352,000 mark will cost $6.5 billion a year, of which the Afghan government would pay $500 million, Nato allies $300 million, and the US paying the remaining amount of $5.7 billion.
Rasmussen praised the growth of the Afghan security forces in the past 12 years and emphasised the continued support, advisory and training role of the Nato allies after 2014 when their combat mission ends.
The defense ministers meeting involved all 50 members of the Isaf coalition, the defense minister of Afghanistan and representatives from the United Nations and the European Union.
There are around 66,000 US troops in Afghanistan helping over 300,000 Afghan security forces fight insurgency.