Prime Minister John Key revealed yesterday that New Zealand recently rebuffed a bid by Australia to form an Anzac training unit in Uruzgan province in Afghanistan.
But he said a small medical team that had returned from Kandahar could go there.
The original request had been for between 20-50 extra troops from New Zealand. Mr Key said former Australian Prime Minister Kevin Rudd asked him last year to consider joining forces with Australian troops already in Uruzgan.
About 1000 of Australia's 1500 troops in Afghanistan are in Uruzgan province working jointly with Dutch forces to train the Afghan National Army and police, and work on reconstruction.
Eleven of Australia's 16 war fatalities have been in Uruzgan.
The Dutch are pulling out in August and Australia has been trying to attract replacement forces.
Mr Key said he told Mr Rudd about six weeks ago that a New Zealand contribution there would not be possible.
The security risk and existing commitments ruled out involvement.
"We are actually pretty fully engaged in Afghanistan," Mr Key told reporters yesterday at Parliament.
The SAS are in Kabul until March next year and the provincial reconstruction team was to be replaced over five years with civilians.
But all is not going according to plan, Mr Key indicated yesterday.
"The withdrawal of people is proving to be a little slower than we originally thought."
Mr Key considered the Australian option when he visited Afghanistan in April "but in the final analysis decided we should turn that request down".
He has previously expressed concerns about the dangers of training because of the risks in having to accompany the inexperienced trainees outside compounds.
Mr Key said the main reason was that it would not be possible for New Zealand troops to train people inside a base and he had made some quite strong statements about not wanting to train people "over the wire".
Australian Defence Minister John Faulkner announced last week that the United States would lead a new multinational team in the province, including Australia, and Australia would lead the civilian mission.
It will be part of the Nato-led International Security Assistance Mission Force. Australia anticipates reducing its troop numbers in two to four years.
The province sits between Bamiyan province, where New Zealand's 140-strong provincial reconstruction team is based, and Kandahar and is also known as Oruzgan.
The issue of forming a ready reaction Anzac unit for Pacific deployment was to have been discussed with Mr Rudd this week in a trip to New Zealand which was cancelled when he was deposed last week.