Pharmac is reviewing both BPAC and PreMec operations to ensure it is getting value for money on pharmaceuticals.
Pharmac medical director Dr Peter Moodie says the major review is designed to benefit all three groups.
Four evaluators have been commissioned to look at the reports and data Pharmac receives from the two agencies.
Peter Moodie says some of the issues being looked at include long-term contracts to provide more stability for BPAC and PreMec. They both currently operate on annual contracts. Pharmac is also interested in finding a common method of calculating savings.