Diego Marques-Santos (33) was jailed for three and a-half years when he was sentenced in the Dunedin District Court in April on four counts of stupefying and five of using a document.
He appeared before the Parole Board for the first time last month and was declined early release.
The board heard the high-security inmate at Otago Corrections Facility would be deported to Brazil as soon as the sentence ended.
But panel convener Judge Edwin Paul lamented the lack of detail on what scenario Marques-Santos would face on the outside.
''The concern this board has is we have no substantiated information on what awaits Mr Marques in Brazil,'' he said.
''He tells us his personal property which may have documents confirming his bank accounts, his lawyers in Brazil and that he owns an apartment in Brazil, are still with the police. This board is of the view some urgent inquiries need to be undertaken by Corrections now to determine what Mr Marques' circumstances are in Brazil.''
Marques-Santos met his victims - three in Nelson and two in Dunedin - through the gay dating app Grindr.
He would meet the men, watch them enter their Pins while making an eftpos purchase then, while in their homes, would spike their drinks with Clonazepam.
While the victims were unconscious, he would take their bank card and go on a spending spree.
Marques-Santos stole more than $10,000 in less than a month.
He was originally set to undertake the medium intensity rehabilitation programme while behind bars but was removed ''as a result of concerns around his mental health and his inability to complete a group-based programme'', the Parole Board noted.
''His time in prison has been uneven to say the least. He has made various allegations against fellow cellmates, prison staff, and the suggestion is he can be manipulative,'' Judge Paul said.
While before the board, however, Marques-Santos was able to engage with the panel ''in a polite and respectful way''.
He will next come before the board in May. Judge Paul said it was ''critical'' that information about Marques-Santos' circumstances was uncovered by then.
