New Zealand police have raided the properties of several prominent harness racing identities as part of an investigation into alleged race fixing.

A police statement said they had conducted search warrants at eight properties in Christchurch, one in Invercargill and another in Manawatu as part of Operation Inca -- an investigation into alleged race-fixing in the harness racing industry.

"Today's warrants were the result of a long-running investigation by the National Organised Crime Group into alleged corruption within the harness racing industry," national manager Criminal Investigations, Detective Superintendent Tim Anderson said.

"Police take such allegations very seriously and are committed to working with the relevant bodies to ensure New Zealand sport is corruption-free.

"The investigation began with information supplied by the Racing Integrity Unit.

Police have been working in partnership with the RIU and other relevant organisations throughout the investigation."

Racing Minister Winston Peters expressed deep disappointment at the allegations.

"This is a sad development. New Zealanders need to have confidence that the racing industry has integrity and is not above the law," Peters said.

"It highlights how important it is that we have a strong, independent authority like the Racing Integrity Unit to ensure offending behaviour is brought to light. We can have confidence that the system is working."