SAS troops were part of a raid on a building in the Afghan capital in which two guards were killed, the Defence Force has confirmed.
The Defence Force is not saying how many New Zealanders were involved.
It says the joint International Security Assistance Force (ISAF) and Afghan National Security Force operation was acting on intelligence indicating two parked vehicles in Kabul were thought to be loaded with explosives.
The British newspaper The Times is reporting that a man who was in the building claimed two of the troops involved were from New Zealand and identified themselves by giving first names, before apologising for the two guards' deaths.
The pair turned out to have been guarding an armoured car firm.
Investigation by unit involved
An ISAF spokesperson in Afghanistan, Captain Ryan Donald, says the unit involved is investigating.
He says it's trying to find out what happened and if there were any - in his words - "disconnects".
Under a deal made in 2008, Afghan authorities have to approve and lead all security operations in the capital.
The Afghan government says the raid violated that agreement, but ISAF says correct procedures were followed in the operation, which came after a threat to the United States Embassy.