New Zealand police have made three further arrests as part of their investigation into alleged race-fixing.

Three men, aged 30, 42 and 49, were due to appear in Christchurch District Court on Wednesday afternoon on multiple drug-related charges.

The 30-year-old man is also facing a charge of unlawful possession of a restricted weapon.

Ten people have now been charged in relation to Operation Inca -- the National Organised Crime Group investigation into alleged corruption in harness racing.

Wednesday's arrests were the result of a further six search warrants conducted in Christchurch, taking the total number of search warrants to 17.

On Tuesday, police raided the properties of several prominent harness racing identities mainly in the Christchurch area and charged seven people.