Wellington  - New Zealand has sent 71 troops from its Special Air Services to join the NATO war effort in Afghanistan, Prime Minister John Key said Monday.

He said New Zealand was supporting the administration of President Hamid Karzai to try to stabilize Afghanistan despite doubts about the lead Karzai holds in preliminary results from August's presidential election after charges of election fraud.

Key said a task group of the New Zealand troops would be deployed for 12 to 18 months. He refused to specify what their mission was but said the special forces soldiers would not be allowed to extend their operations into Pakistan.

It was the fourth time New Zealand has sent its elite SAS forces to Afghanistan since the September 11, 2001, terrorist attacks on the United States.

Another group of about 130 New Zealand troops is working in central Afghanistan's Bamiyan province on civilian reconstruction projects.

Key made the announcement days after the latest troops arrived in Afghanistan and shortly before he was scheduled to leave for New York to attend the United Nations General Assembly and have a possible informal meeting with US President Barack Obama. (dpa)