Police investigations into the death of an Otago remand prisoner have been stepped up following the involvement of New Zealand's police watchdog in the case.
The Independent Police Conduct Authority (IPCA) received a complaint from Wellington drug and alcohol counsellor Roger Brooking in March regarding patient treatment at Otago Corrections Facility, Radio New Zealand reported.
The February 2011 death of Jai Davis had to be taken seriously, Mr Brooking told Radio NZ.
One month later, police dedicated a full-time team to the investigation. However they stated an investigation into the case had been ongoing since Davis died two-and-a-half years ago.
The IPCA confirmed this morning they had received a complaint into the "adequacy and length of time" of the police investigation into Davis' death.
"The complaint is currently being independently investigated by the Authority," they said in a statement.
"The same complainant has also brought the death of another prisoner, Richard Barriball, to the Authority's attention."
Barriball, who was also a prisoner at Otago Corrections Facility, died in October 2010.
Both Barriball and Davis were considered at-risk prisoners.
"The Authority has asked Police to consider any issues raised about Mr Barriball's death during their investigation of Mr Davis' death. The Authority is not dealing separately with this matter," the IPCA said.
Mr Brooking told Radio NZ this morning the two deaths suggested there were serious concerns about the level of medical and health care in Otago Prison.
"Well all I can say is that I did make a complaint to the IPCA about the fact that it did take two years for an investigation to begin.
"I note that the corrections department has a rating system for its prisons and the Otago Prison is at the bottom of the ratings," he said.
Dunedin police said in a statement the Jai Davis investigation had been complex was likely to conclude "in the next few months".
"With regard to Richard Barriball we confirm that we have been reviewing the investigation file in relation to his death.
"These are both current investigations and police are not able to comment further until they are completed."
