New Zealand Commerce Act 1986 27: Do not enter into or give effect to contracts, arrangements or understandings that substantially lessen competition

What does 27 require?

No person may make a contract or arrangement, or reach an understanding, that contains a provision whose purpose, effect or likely effect is to substantially lessen competition in a market, and no person may give effect to such a provision. The prohibition reaches informal understandings and ongoing conduct under older agreements, and competition is assessed in the properly defined market with the efficiency considerations the Act allows.