Police in Fiji have confirmed a New Zealand man is in custody for questioning.
It is not clear why Jagath Karunaratne has been detained.
Relatives are concerned because Mr Karunaratne has a heart condition and they say he is not getting medical care, Radio New Zealand International reports.
Fiji Assistant Commissioner of Police Henry Brown says the New Zealander is being well looked after and has been seen by consular officials.
But an Auckland-based family member, Rajesh Singh, says family visited Mr Karunaratne again on Wednesday morning and fear for his well-being as he has not been allowed to see a doctor.
Mr Brown says no charges have been laid yet against the IT professional who he says is among a group of people being questioned.
The official says he is the only foreign national in the group.