"Dissolving the private security companies is a serious programme that the government of Afghanistan will execute," Waheed Omer told reporters, adding that "very soon the president of Afghanistan will set a deadline".
Omer said Karzai had spoken to his Western backers as well as leaders of the US and NATO's International Security Assistance Force (ISAF) who contract the companies to safeguard many aspects of their work, including supply convoys.
"Over the past few days the president held discussions with officials from our allied countries, with NATO and ISAF leaders and all those involved," said Omer.
He said private security companies employ 30-40,000 armed personnel throughout Afghanistan.
Karzai has accused the companies of operating in parallel to Afghan security forces, and of diverting critical resources needed to train army and police.
"If the dissolution is not carried out under a precise programme there will definitely be consequences.
"The government of Afghanistan has that in mind and is working... (to) ensure that those working for these companies be recruited by the Afghan national security forces," said Omer.
He added that the international community must help with the transition to dissolve the private security firms.
"This is a programme that will be executed at any cost," he said.
