The New Zealand Defence Force (NZDF) hoped to learn in the next few months whether a potential burial site was worth excavating on the Kiribati atoll.
A team from JPac (Joint Prisoners of War, Missing in Action Accounting Command) would soon be on site to investigate an area identified as a potential mass grave from aerial photographs taken before the atoll was destroyed by naval gun fire towards the end of World War 2.
NZDF director of commemorations, heritage and protocol John McLeod said if the JPac team discovered anything to suggest New Zealand remains were in the vicinity, a full excavation could follow.
But he did not want to get relatives' hopes up and said the search was "one step at a time".
More than 5000 Japanese remained buried on Tarawa, which was extensively damaged in the war.
"The impact of a naval shell will shift a small hill, so if remains were buried two or three feet down and naval gunfire landed anywhere nearby it would shift them. The whole island was hit by naval gunfire, then the Americans bulldozed a lot of it to build a runway," Mr McLeod said.
The defence force was responsible for any New Zealander missing in action, including the 17 coastwatchers beheaded by their Japanese captors on October 15, 1942.
Among them were Clifford Pearsall, of Lawrence, and Arthur Heenan, of Middlemarch.
Mr Heenan's younger brother, Bob Heenan (86), who lives in Mosgiel, said he held little hope of his brother's remains being found and returned.
"It's been such a long time and they don't seem to be making very much progress. There are so many bodies there, it would be very difficult," he said.
Mr McLeod said there had been "quite a few" efforts to locate New Zealand remains on Tarawa, including immediately after World War 2.
In February, the defence force learnt of a possible burial site, identified last year by JPac experts, which was underneath a modern cemetery.
"The plan is to do some exploratory work to identify whether in fact that is a possible location.
"Based on what is found, New Zealand would then look at doing an excavation once we had the necessary approvals from the local authorities," Mr McLeod said.
Remains would have to be forensically examined to see whether they were of New Zealanders.
"Wherever you dig on the island, you'll find bones. That's a fact of life. All we can do is give it our best shot," he said.
The NZDF would keep looking for coastwatchers' remains.
"There's a commitment to provide some comfort for families. We may never find anything, but we owe it to their memory to keep trying," Mr McLeod said.
Coastwatchers were recognised during a commemoration at the National War Memorial in Wellington this week, on the 70th anniversary of the Tarawa execution.
American organisation History Flight had offered to assist any New Zealand effort to locate, identify and retrieve coastwatchers' bodies from Tarawa.
The non-profit organisation had searched out and retrieved missing American World War 2 servicemen from the Pacific and identified three locations on Tarawa where it believed New Zealand coastwatchers were buried.
