A long-running dispute between the Southern District Health Board (DHB) and a doctors' group is now in the hands of the Serious Fraud Office (SFO).
The DHB has been at loggerheads with South Link Health over spending since 2002.
The DHB said it became aware in late 2013 that the possibility of fraud could not be excluded and referred the matter to the forensic investigation firm, Beattie Varley Limited.
It said following advice from the firm, it had now asked the SFO to look at the case.
The DHB said it met with South Link Health today and told them about the referral, but still hoped to negotiate a settlement as a separate issue to any potential fraud.
In February, the doctors' group said it was astonished to be the focus of possible fraud over a contract with health boards.