New Zealand confirmed Monday that its troops would end a decade-long deployment in Afghanistan at the end of April next year, about six months earlier than originally planned.

The withdrawal was flagged last month after the deaths of three soldiers, two men and a woman, in a roadside bomb attack in the central province of Bamiyan, where New Zealanders have been deployed since 2003.

Defence Minister Jonathan Coleman said arrangements for New Zealand's 145-member provincial reconstruction team (PRT) in Bamiyan to return home had been now been finalised with the International Security Assistance Force.

Coleman said the New Zealanders' efforts had helped ensure Bamiyan was one of the first provinces where responsibility for security was handed back to local control.

"We should not underestimate the challenges Afghanistan will continue to face," he said in a statement.

"We should also acknowledge the courage and sacrifice of those who have lost their lives while on active service in the province."

A total of 10 New Zealand troops have died in Afghanistan, with five of the fatalities coming last month.

The government has denied a link between the recent deaths and the PRT troops' early exit, saying the withdrawal plan had been on the table for months.

A separate New Zealand deployment of about 40 elite Special Air Services (SAS) troops based in Kabul ended its mission in March this year.

Foreign Minister Murray McCully said New Zealand would maintain a development role in Bamiyan province and provide support for army officer training in Afghanistan.