The New Zealand embassy in Poland is doing all it can to return the body of corporal Dominic Abelen home.
The soldier was on leave without pay from the Army when he died fighting against Russian forces in Ukraine.
The Ministry of Foreign Affairs (MFAT) has confirmed its embassy in Poland's capital Warsaw is working with officials in Ukraine to try to repatriate the soldier's body.
Earlier today, Prime Minister Jacinda Ardern would not be drawn on whether she had information to suggest that Abelen's body was in Russian hands.
"This is an area where both the information is uncertain and also, I'm just not in a position to provide it ... and this is out of huge respect for the family as well."
New Zealand did not have diplomatic staff on the ground in Ukraine, which made it difficult to be certain of the information being received, Ardern said.
Massey University centre for defence and security studies lecturer Terry Johanson, who is a retired lieutenant colonel, said Russia might have demands if the body was in their territory.
It could mean Russia putting pressure on New Zealand to stop providing any training and logistical support from afar, Johanson said.
"New Zealand is not directly in the combat zone in an official capacity. Russia could ask for that support to be withdrawn from Ukraine in return for Dominic Abelen's body to be handed over, if Russia has the body in possession."
However, former defence minister Wayne Mapp did not believe Russia would stoop that low, even in the middle of its deadly invasion.
"I think it's probably a bit unlikely that they will do that. But frankly, New Zealand can't succumb to that sort of blackmail, but there has been, even in the process of war, things of this nature such as exchange of people, including bodies, does take place."
Mapp said he was confident officials were doing all they could to return the soldier's body home.
"Any New Zealander, no matter what their circumstance, caught in a tragedy overseas, MFAT always stands by to help and in this instance, they'll do everything they reasonably can," he said.
"This is why we have trained diplomats. They know how to negotiate with foreign governments."
It was an awkward situation for officials because in the past, if any Armed Force personnel joined an offshore group involved in warfare they would have resigned before leaving, he said.