As few as a half-dozen former prisoners deported from Australia could stretch rehabilitation services in Otago to the limit.
Prisoners Aid and Rehabilitation Society (Pars) Otago manager Colin Hall said the organisation would be unable to cope with an influx of deported prisoners amid fears 1000 convicts would be sent here from Australia during the next few years.
More than 160 former prisoners were deported from Australia this year, according to the New Zealand Police.
It is not known how many now live in Otago.
Those figures are in contrast to figures supplied by the Australian Government, which said only 80 former prisoners were deported to New Zealand this year.
Pars Otago helped one deportee last year, but feared more might soon be seeking their services after Australia changed its Migration Act in December last year.
Pars is an non-government agency that receives some funding from the Department of Corrections to help former prisoners reintegrate into society. However, there was no funding provided for Australian deportees.
''If there was a big influx of people it could put a strain on things because we aren't funded to deal with them but someone has got to deal with them,'' Mr Hall said.
''They are ex-prisoners after all. If they are released from prison, whether it's here or Australia, and they arrive on our doorstep we will assist them.''
Pars Otago had five people in supported accommodation and provided about 20 others with help at any one time; as few as another six unfunded prisoners could affect its ability to deliver services and accommodation.
The situation was further complicated by the lack of information about former Australian prisoners, he said.
The Australian deportee Pars Otago helped last year referred himself and the only information the organisation had about him was provided by him.
''We didn't know a whole lot about him,'' Mr Hall said.
The man arrived with no support network or contacts and was reliant on Pars for help.
The lack of information could complicate Pars' ability to find suitable accommodation, especially if the criminal had a history of sexual offending.
Attempts by the Otago Daily Times to find out how many deported former prisoners were sent and lived within Dunedin and Otago were unsuccessful.
Requests for information to the Department of Immigration and Border Protection in Australia were referred to the Minister, Peter Dutton.
A media adviser for Mr Dutton said information on port of entry into New Zealand for deported former prisoners was not collated and referred the ODT to New Zealand authorities for further comment.
The spokeswoman said 80 New Zealanders were deported from Australia this year under the new rules.
A spokesman for the Ministry of Business, Innovation and Employment said New Zealand police or Australian authorities would have to provide the information.
A police spokesman said police were aware of 167 former Australian prisoners being deported to New Zealand this year with the vast majority entering through Auckland.
However, that did not indicate where the offenders resided and they had no obligation to communicate with police.
''In general we can say that New Zealand police regularly liaise with Australian authorities regarding deported persons from Australia,'' he said.
''When NZ police are informed about an upcoming deportation, and where necessary, we seek to obtain all relevant information about the person, including their conviction history and details about their offending.
"We endeavour to meet those individuals on their return to New Zealand to establish their intentions, including where they intend to live.
''This information is passed to the relevant police district. The district can then work with agencies to develop an appropriate response within the current legislation, including managing any risk posed by the individual.
''These individuals are under no obligation to engage with police on their arrival in New Zealand unless they are wanted in connection with any matters here.''
Mr Dutton's media adviser could not explain the disparity between the figures of the Australian government and New Zealand police.
Police figures were more than twice what Australian authorities indicated.
''I can't speak for their numbers as I don't know what date range they are using,'' she said.
New Zealand police confirmed their figures were for the same timeframe.
Earlier this year, it was revealed a convicted sex offender from Perth was deported to the South Island without the knowledge of New Zealand authorities.
Authorities only became aware of his presence in New Zealand after his daughter alerted them.
Last month, Justice Minister Amy Adams and Police Minister Michael Woodhouse signed an information-sharing arrangement with Australia regarding deportations.
The Government is working on a supervision regime for deported offenders.
Prime Minister John Key this week said up to 1000 criminals could eventually be deported from Australia to New Zealand.
