Two New Zealanders sent to Japan to assist in the recovery effort have tested positive for low-levels of radiation.
The magnitude 9.0 earthquake and tsunami on Friday cut power to the Fukushima nuclear plant, leading to explosions and a fire that is producing a cloud of life-threatening radiation.
There is now a no-fly zone over a 30km radius around the stricken plant.
Prime Minister John Key said this afternoon that two New Zealanders, a Fire Service urban search and rescue team (USAR) member and an interpreter, were in a Black Hawk helicopter forced to land 20km from the exclusion zone in Fukishima because of ice on its blades.
Mr Key said the men, along with four Australians, were tested for radiation contamination when they arrived back at their base.
The two New Zealanders and two of the Australians had very low levels of radiation contamination on them, Mr Key said.
The group had been through a decontamination process, and Mr Key said it was not believed that they were suffering any health risks.
"We've been in constant contact with the National Radiation Laboratory and we're quite comfortable about their position."
The men had then used ground transport and it was believed they had picked up radiation on their boots in the transport.
They would remain in Japan, Mr Key said.
"At the moment they're staying there, we continue to assess their relevance and their role there.
"As long as there is a rescue operation going on then New Zealand will stay engaged."
The Ministry of Foreign Affairs and Trade said tonight there were no other reports of New Zealand casualties or injuries and it had confirmed 1883 New Zealanders were safe and well in Japan.
There were concerns about the safety of one New Zealander, but the ministry would not reveal any details of that person.
Meanwhile, New Zealand's 48-strong USAR team, working alongside Japanese civil defence workers and an Australian USAR team, has found no survivors, as they scour the towering piles of wreckage that was once the coastal town on Minamisanriku
"We are working in a scene of utter devastation, among the debris of many thousands of timber structures and destroyed vehicles," team leader and New Zealand Fire Service Special Operations manager Jim Stuart-Black said.
"It is painstaking and careful work and we are all committed to the task."
He said the team continued to monitor radiation levels following the damage done to the nuclear power stations south of Minamisanriku, and there had been no sign of any increase beyond the normal background levels.
He described the slightly elevated levels of radiation to the two New Zealand team members as a minor incident.
"The levels are not high and we have been reassured that there is no danger to those involved," said Mr Stuart-Black.
NZPA