Andrew Bagshaw, the son of two prominent doctors, has been reported missing while doing voluntary work in war-torn Ukraine.
He went there as a volunteer to assist the people of Ukraine by delivering humanitarian aid.
In a statement via Kiwi Aid and Refugee Evacuation - an NGO working with volunteers in Ukraine - Andrew Bagshaw's parents said their son was volunteering in the war-torn country because he believed it was the morally right thing to do.
Philip and Sue Bagshaw said he had been delivering food and medicines and helping elderly people move from near the battlefront of the war.
Philip Bagshaw is the founder of the Canterbury Charity Hospital while Sue Bagshaw has worked in the youth mental field for more than 30 years.
The couple said agencies in New Zealand and the UK - where their son was born - are working hard to find him.
They said Bagshaw is an "intelligent, independently minded person" who they love dearly, and they are grateful to everyone who is searching for them.
Kiwi K.A.R.E (Kiwi Aid and Refugee Evacuation) director Tenby Powell told RNZ he was in close contact with the parents.
"Clearly the family are very concerned, very upset, at Andrew's disappearance," he said.
"We haven't given up hope, you know there's a number of people in Ukraine who are actively searching for him, including members of the Ukraine armed forces who have been very helpful at trying to identify and locate Andrew."
He said Bagshaw had been missing for two days.
"While in the scheme that might not sound very much under normal circumstances, given where he is, and where he's been operating, it's a long time."
Powell said he had written to the New Zealand ambassador in Poland, Alana Hudson, and the Ukrainian ambassador to Australia and New Zealand, Vasyl Myroshnychenko, who responded quickly.
"There's a tremendous amount of goodwill in the sense that all the agencies, including MFAT [Ministry of Foreign Affairs and Trade] now, are actively trying to locate and assist the Bagshaws in finding Andrew."
In a statement, MFAT said it was aware of reports a dual New Zealand/ British national was missing in Ukraine, and it was in contact with the UK government.
It said there were four New Zealanders registered on SafeTravel as being in Ukraine.
Surgeon Phil Bagshaw was made a Companion of the New Zealand Order of Merit (CNZM) for his services to health in 2019. He helped establish the Canterbury Charity Hospital and now chairs its trust.
The hospital has treated more than 20,000 people since it opened in Christchurch in 2007.
It has been offering free elective day surgeries and medical clinics to people who did not qualify for or could not afford other health care.
Since then, it has grown to four connected buildings, with a new purpose built reception area, kitchen and flat which opened last December.
Andrew Bagshaw's mother Dr Sue Bagshaw has worked in the youth health sector for three decades and is also a senior lecturer in paediatrics at the University of Otago in Christchurch.
She was made a dame companion of the New Zealand Order of Merit for her services to youth health in 2019.
New Zealander Dominic Abelen was killed while fighting Russian forces in Ukraine last year and his body was not able to be repatriated.
Abelen had served with New Zealand Defence Force, but at the time of his death he had been on a period of leave without pay and was not on active duty.
Following his death the military contacted soldiers on leave without pay to stress they could not go to Ukraine as per the 'do not travel' advisory.
A group of New Zealand soldiers were officially deployed in the UK from the end of August 2022 until 31 July 2023 to train Ukranian infantry recruits.