WELLINGTON — New Zealand revealed Monday it was considering an early withdrawal from Afghanistan after three of its soldiers were killed in a roadside bomb attack on their convoy in Bamiyan province.

Prime Minister John Key insisted the plan to pull out early was not linked to the attack, which raises the number of New Zealand soldiers killed in Afghanistan this month to five.

He said New Zealand, which has suffered a total of 10 deaths in Afghanistan, was looking at withdrawing its 145-member provincial reconstruction team in Bamiyan in early 2013, rather than late next year as originally planned.

Key said discussions about an early exit began before August 4, when two soldiers were killed and six wounded in what has been the bloodiest month for New Zealand troops since they deployed in 2003.

"That date, if we confirm that, which we would want to do in the next few weeks, is not something that's changed as a result of these five tragic deaths," he told Radio New Zealand.

He said there had been increased insurgent activity recently in north-east Bamiyan and New Zealand would not "cut and run" before handing over to local authorities.

"It's neither practical, nor sensible, nor right for us just to abandon and cut and run today," he said.

"That wouldn't honour those 10 deaths, it wouldn't mark the enormous amount of work that we've put into Afghanistan and it just isn't the way that New Zealand operates on the international stage."

Key said the latest deaths "underscore the gravity of the situations New Zealand?s soldiers face daily in Afghanistan".

"The three brave soldiers paid the ultimate price for their selfless work, and my thoughts are with their families and friends as they mourn their loved ones," he added.

The New Zealand Defence Force said the three men were in the last vehicle of a convoy that was hit by an an improvised explosive device, northwest of Do Abe where the other two soldiers died on August 4.

Key said the blast was significant and the three soldiers, who were in a humvee, were believed to have died instantly.

Defence Minister Jonathan Coleman said the deaths were "a deep shock to the nation".

"It comes as a significant blow after the other casualties our defence force suffered on August 4," he said in a statement.

Photo by Spc. Bao Huynh [Public domain], via Wikimedia Commons