WELLINGTON - New Zealand troops are to withdraw from strife-torn Syria this week as the United Nations Supervision Mission (UNSMIS) ends, the New Zealand government announced Wednesday.

After the UN Security Council mandate for the mission expired on Aug 19, the UN had indicated it would have all international military observers, including New Zealand Defence Force (NZDF) personnel, out of Syria by Aug 23, New Zealand Foreign Affairs Minister Murray McCully said in a statement.

"We acknowledge the bravery and commitment of the NZDF officers who have served in a dangerous volatile situation. Unfortunately, the worsening violence in Syria has made it impossible for the mission to carry out its mandated task," McCully said.

"New Zealand was quick to provide assistance to the UN and deploy personnel to support Kofi Annan's six-point plan to end the violence and monitor a ceasefire," he said.

"We once again urge the Security Council to display leadership and to work collaboratively to end the humanitarian crisis in Syria."

NZDF troops have been in Syria for three months.

Initially six personnel were deployed, but three military observers were withdrawn following the halving of overall UNSMIS numbers in late July, New Zealand Defence Minister Jonathan Coleman said in the statement.

New Zealand remained committed to working closely with the international community in pursuing an end to the Syrian conflict, he said.